compat/regex: use the regex engine from gawk for compat

Change the regex engine in compat to use the gawk engine from the
gawk-devel module in gawk CVS. This engine supports the REG_STARTEND
flag, which was optionally available in Git since v1.7.2-rc0~77^2~1.

The source was grabbed from cvs.savannah.gnu.org:/sources/gawk, and
these are the upstream versions of the files being included:

    regcomp.c               1.4
    regex.h                 1.3
    regex.h                 1.3
    regex_internal.c        1.3
    regex_internal.h        1.3
    regexec.c               1.3

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/compat/regex/regex.h b/compat/regex/regex.h
index 6eb64f1..de93327 100644
--- a/compat/regex/regex.h
+++ b/compat/regex/regex.h
@@ -1,70 +1,87 @@
 /* Definitions for data structures and routines for the regular
-   expression library, version 0.12.
+   expression library.
+   Copyright (C) 1985,1989-93,1995-98,2000,2001,2002,2003,2005,2006,2008
+   Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
 
-   Copyright (C) 1985, 1989, 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
 
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2, or (at your option)
-   any later version.
-
-   This program is distributed in the hope that it will be useful,
+   The GNU C Library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
 
-   You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software
-   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+   02110-1301 USA.  */
 
-#ifndef __REGEXP_LIBRARY_H__
-#define __REGEXP_LIBRARY_H__
+#ifndef _REGEX_H
+#define _REGEX_H 1
 
-/* POSIX says that <sys/types.h> must be included (by the caller) before
-   <regex.h>.  */
-
-#ifdef VMS
-/* VMS doesn't have `size_t' in <sys/types.h>, even though POSIX says it
-   should be there.  */
+#ifdef HAVE_STDDEF_H
 #include <stddef.h>
 #endif
 
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+
+#ifndef _LIBC
+#define __USE_GNU	1
+#endif
+
+/* Allow the use in C++ code.  */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* The following two types have to be signed and unsigned integer type
+   wide enough to hold a value of a pointer.  For most ANSI compilers
+   ptrdiff_t and size_t should be likely OK.  Still size of these two
+   types is 2 for Microsoft C.  Ugh... */
+typedef long int s_reg_t;
+typedef unsigned long int active_reg_t;
 
 /* The following bits are used to determine the regexp syntax we
    recognize.  The set/not-set meanings are chosen so that Emacs syntax
    remains the value 0.  The bits are given in alphabetical order, and
    the definitions shifted by one from the previous bit; thus, when we
    add or remove a bit, only one other definition need change.  */
-typedef unsigned reg_syntax_t;
+typedef unsigned long int reg_syntax_t;
 
+#ifdef __USE_GNU
 /* If this bit is not set, then \ inside a bracket expression is literal.
    If set, then such a \ quotes the following character.  */
-#define RE_BACKSLASH_ESCAPE_IN_LISTS (1)
+# define RE_BACKSLASH_ESCAPE_IN_LISTS ((unsigned long int) 1)
 
 /* If this bit is not set, then + and ? are operators, and \+ and \? are
      literals.
    If set, then \+ and \? are operators and + and ? are literals.  */
-#define RE_BK_PLUS_QM (RE_BACKSLASH_ESCAPE_IN_LISTS << 1)
+# define RE_BK_PLUS_QM (RE_BACKSLASH_ESCAPE_IN_LISTS << 1)
 
 /* If this bit is set, then character classes are supported.  They are:
      [:alpha:], [:upper:], [:lower:],  [:digit:], [:alnum:], [:xdigit:],
      [:space:], [:print:], [:punct:], [:graph:], and [:cntrl:].
    If not set, then character classes are not supported.  */
-#define RE_CHAR_CLASSES (RE_BK_PLUS_QM << 1)
+# define RE_CHAR_CLASSES (RE_BK_PLUS_QM << 1)
 
 /* If this bit is set, then ^ and $ are always anchors (outside bracket
      expressions, of course).
    If this bit is not set, then it depends:
-	^  is an anchor if it is at the beginning of a regular
-	   expression or after an open-group or an alternation operator;
-	$  is an anchor if it is at the end of a regular expression, or
-	   before a close-group or an alternation operator.
+        ^  is an anchor if it is at the beginning of a regular
+           expression or after an open-group or an alternation operator;
+        $  is an anchor if it is at the end of a regular expression, or
+           before a close-group or an alternation operator.
 
    This bit could be (re)combined with RE_CONTEXT_INDEP_OPS, because
    POSIX draft 11.2 says that * etc. in leading positions is undefined.
    We already implemented a previous draft which made those constructs
    invalid, though, so we haven't changed the code back.  */
-#define RE_CONTEXT_INDEP_ANCHORS (RE_CHAR_CLASSES << 1)
+# define RE_CONTEXT_INDEP_ANCHORS (RE_CHAR_CLASSES << 1)
 
 /* If this bit is set, then special characters are always special
      regardless of where they are in the pattern.
@@ -72,63 +89,94 @@
      some contexts; otherwise they are ordinary.  Specifically,
      * + ? and intervals are only special when not after the beginning,
      open-group, or alternation operator.  */
-#define RE_CONTEXT_INDEP_OPS (RE_CONTEXT_INDEP_ANCHORS << 1)
+# define RE_CONTEXT_INDEP_OPS (RE_CONTEXT_INDEP_ANCHORS << 1)
 
 /* If this bit is set, then *, +, ?, and { cannot be first in an re or
      immediately after an alternation or begin-group operator.  */
-#define RE_CONTEXT_INVALID_OPS (RE_CONTEXT_INDEP_OPS << 1)
+# define RE_CONTEXT_INVALID_OPS (RE_CONTEXT_INDEP_OPS << 1)
 
 /* If this bit is set, then . matches newline.
    If not set, then it doesn't.  */
-#define RE_DOT_NEWLINE (RE_CONTEXT_INVALID_OPS << 1)
+# define RE_DOT_NEWLINE (RE_CONTEXT_INVALID_OPS << 1)
 
 /* If this bit is set, then . doesn't match NUL.
    If not set, then it does.  */
-#define RE_DOT_NOT_NULL (RE_DOT_NEWLINE << 1)
+# define RE_DOT_NOT_NULL (RE_DOT_NEWLINE << 1)
 
 /* If this bit is set, nonmatching lists [^...] do not match newline.
    If not set, they do.  */
-#define RE_HAT_LISTS_NOT_NEWLINE (RE_DOT_NOT_NULL << 1)
+# define RE_HAT_LISTS_NOT_NEWLINE (RE_DOT_NOT_NULL << 1)
 
 /* If this bit is set, either \{...\} or {...} defines an
      interval, depending on RE_NO_BK_BRACES.
    If not set, \{, \}, {, and } are literals.  */
-#define RE_INTERVALS (RE_HAT_LISTS_NOT_NEWLINE << 1)
+# define RE_INTERVALS (RE_HAT_LISTS_NOT_NEWLINE << 1)
 
 /* If this bit is set, +, ? and | aren't recognized as operators.
    If not set, they are.  */
-#define RE_LIMITED_OPS (RE_INTERVALS << 1)
+# define RE_LIMITED_OPS (RE_INTERVALS << 1)
 
 /* If this bit is set, newline is an alternation operator.
    If not set, newline is literal.  */
-#define RE_NEWLINE_ALT (RE_LIMITED_OPS << 1)
+# define RE_NEWLINE_ALT (RE_LIMITED_OPS << 1)
 
 /* If this bit is set, then `{...}' defines an interval, and \{ and \}
      are literals.
   If not set, then `\{...\}' defines an interval.  */
-#define RE_NO_BK_BRACES (RE_NEWLINE_ALT << 1)
+# define RE_NO_BK_BRACES (RE_NEWLINE_ALT << 1)
 
 /* If this bit is set, (...) defines a group, and \( and \) are literals.
    If not set, \(...\) defines a group, and ( and ) are literals.  */
-#define RE_NO_BK_PARENS (RE_NO_BK_BRACES << 1)
+# define RE_NO_BK_PARENS (RE_NO_BK_BRACES << 1)
 
 /* If this bit is set, then \<digit> matches <digit>.
    If not set, then \<digit> is a back-reference.  */
-#define RE_NO_BK_REFS (RE_NO_BK_PARENS << 1)
+# define RE_NO_BK_REFS (RE_NO_BK_PARENS << 1)
 
 /* If this bit is set, then | is an alternation operator, and \| is literal.
    If not set, then \| is an alternation operator, and | is literal.  */
-#define RE_NO_BK_VBAR (RE_NO_BK_REFS << 1)
+# define RE_NO_BK_VBAR (RE_NO_BK_REFS << 1)
 
 /* If this bit is set, then an ending range point collating higher
      than the starting range point, as in [z-a], is invalid.
    If not set, then when ending range point collates higher than the
      starting range point, the range is ignored.  */
-#define RE_NO_EMPTY_RANGES (RE_NO_BK_VBAR << 1)
+# define RE_NO_EMPTY_RANGES (RE_NO_BK_VBAR << 1)
 
 /* If this bit is set, then an unmatched ) is ordinary.
    If not set, then an unmatched ) is invalid.  */
-#define RE_UNMATCHED_RIGHT_PAREN_ORD (RE_NO_EMPTY_RANGES << 1)
+# define RE_UNMATCHED_RIGHT_PAREN_ORD (RE_NO_EMPTY_RANGES << 1)
+
+/* If this bit is set, succeed as soon as we match the whole pattern,
+   without further backtracking.  */
+# define RE_NO_POSIX_BACKTRACKING (RE_UNMATCHED_RIGHT_PAREN_ORD << 1)
+
+/* If this bit is set, do not process the GNU regex operators.
+   If not set, then the GNU regex operators are recognized. */
+# define RE_NO_GNU_OPS (RE_NO_POSIX_BACKTRACKING << 1)
+
+/* If this bit is set, a syntactically invalid interval is treated as
+   a string of ordinary characters.  For example, the ERE 'a{1' is
+   treated as 'a\{1'.  */
+# define RE_INVALID_INTERVAL_ORD (RE_NO_GNU_OPS << 1)
+
+/* If this bit is set, then ignore case when matching.
+   If not set, then case is significant.  */
+# define RE_ICASE (RE_INVALID_INTERVAL_ORD << 1)
+
+/* This bit is used internally like RE_CONTEXT_INDEP_ANCHORS but only
+   for ^, because it is difficult to scan the regex backwards to find
+   whether ^ should be special.  */
+# define RE_CARET_ANCHORS_HERE (RE_ICASE << 1)
+
+/* If this bit is set, then \{ cannot be first in an bre or
+   immediately after an alternation or begin-group operator.  */
+# define RE_CONTEXT_INVALID_DUP (RE_CARET_ANCHORS_HERE << 1)
+
+/* If this bit is set, then no_sub will be set to 1 during
+   re_compile_pattern.  */
+#define RE_NO_SUB (RE_CONTEXT_INVALID_DUP << 1)
+#endif
 
 /* This global variable defines the particular regexp syntax to use (for
    some interfaces).  When a regexp is compiled, the syntax used is
@@ -136,6 +184,7 @@
    already-compiled regexps.  */
 extern reg_syntax_t re_syntax_options;
 
+#ifdef __USE_GNU
 /* Define combinations of the above bits for the standard possibilities.
    (The [[[ comments delimit what gets put into the Texinfo file, so
    don't delete them!)  */
@@ -143,13 +192,22 @@
 #define RE_SYNTAX_EMACS 0
 
 #define RE_SYNTAX_AWK							\
-  (RE_BACKSLASH_ESCAPE_IN_LISTS | RE_DOT_NOT_NULL			\
-   | RE_NO_BK_PARENS            | RE_NO_BK_REFS				\
-   | RE_NO_BK_VBAR               | RE_NO_EMPTY_RANGES			\
-   | RE_UNMATCHED_RIGHT_PAREN_ORD)
+  (RE_BACKSLASH_ESCAPE_IN_LISTS   | RE_DOT_NOT_NULL			\
+   | RE_NO_BK_PARENS              | RE_NO_BK_REFS			\
+   | RE_NO_BK_VBAR                | RE_NO_EMPTY_RANGES			\
+   | RE_DOT_NEWLINE		  | RE_CONTEXT_INDEP_ANCHORS		\
+   | RE_UNMATCHED_RIGHT_PAREN_ORD | RE_NO_GNU_OPS)
 
-#define RE_SYNTAX_POSIX_AWK 						\
-  (RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS)
+#define RE_SYNTAX_GNU_AWK						\
+  ((RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS		\
+   | RE_INVALID_INTERVAL_ORD)						\
+   & ~(RE_DOT_NOT_NULL | RE_CONTEXT_INDEP_OPS				\
+       | RE_CONTEXT_INVALID_OPS ))
+
+#define RE_SYNTAX_POSIX_AWK						\
+  (RE_SYNTAX_POSIX_EXTENDED | RE_BACKSLASH_ESCAPE_IN_LISTS		\
+   | RE_INTERVALS	    | RE_NO_GNU_OPS				\
+   | RE_INVALID_INTERVAL_ORD)
 
 #define RE_SYNTAX_GREP							\
   (RE_BK_PLUS_QM              | RE_CHAR_CLASSES				\
@@ -163,7 +221,8 @@
    | RE_NO_BK_VBAR)
 
 #define RE_SYNTAX_POSIX_EGREP						\
-  (RE_SYNTAX_EGREP | RE_INTERVALS | RE_NO_BK_BRACES)
+  (RE_SYNTAX_EGREP | RE_INTERVALS | RE_NO_BK_BRACES			\
+   | RE_INVALID_INTERVAL_ORD)
 
 /* P1003.2/D11.2, section 4.20.7.1, lines 5078ff.  */
 #define RE_SYNTAX_ED RE_SYNTAX_POSIX_BASIC
@@ -176,7 +235,7 @@
    | RE_INTERVALS  | RE_NO_EMPTY_RANGES)
 
 #define RE_SYNTAX_POSIX_BASIC						\
-  (_RE_SYNTAX_POSIX_COMMON | RE_BK_PLUS_QM)
+  (_RE_SYNTAX_POSIX_COMMON | RE_BK_PLUS_QM | RE_CONTEXT_INVALID_DUP)
 
 /* Differs from ..._POSIX_BASIC only in that RE_BK_PLUS_QM becomes
    RE_LIMITED_OPS, i.e., \? \+ \| are not recognized.  Actually, this
@@ -185,13 +244,13 @@
   (_RE_SYNTAX_POSIX_COMMON | RE_LIMITED_OPS)
 
 #define RE_SYNTAX_POSIX_EXTENDED					\
-  (_RE_SYNTAX_POSIX_COMMON | RE_CONTEXT_INDEP_ANCHORS			\
-   | RE_CONTEXT_INDEP_OPS  | RE_NO_BK_BRACES				\
-   | RE_NO_BK_PARENS       | RE_NO_BK_VBAR				\
-   | RE_UNMATCHED_RIGHT_PAREN_ORD)
+  (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS			\
+   | RE_CONTEXT_INDEP_OPS   | RE_NO_BK_BRACES				\
+   | RE_NO_BK_PARENS        | RE_NO_BK_VBAR				\
+   | RE_CONTEXT_INVALID_OPS | RE_UNMATCHED_RIGHT_PAREN_ORD)
 
-/* Differs from ..._POSIX_EXTENDED in that RE_CONTEXT_INVALID_OPS
-   replaces RE_CONTEXT_INDEP_OPS and RE_NO_BK_REFS is added.  */
+/* Differs from ..._POSIX_EXTENDED in that RE_CONTEXT_INDEP_OPS is
+   removed and RE_NO_BK_REFS is added.  */
 #define RE_SYNTAX_POSIX_MINIMAL_EXTENDED				\
   (_RE_SYNTAX_POSIX_COMMON  | RE_CONTEXT_INDEP_ANCHORS			\
    | RE_CONTEXT_INVALID_OPS | RE_NO_BK_BRACES				\
@@ -202,10 +261,12 @@
 /* Maximum number of duplicates an interval can allow.  Some systems
    (erroneously) define this in other header files, but we want our
    value, so remove any previous define.  */
-#ifdef RE_DUP_MAX
-#undef RE_DUP_MAX
+# ifdef RE_DUP_MAX
+#  undef RE_DUP_MAX
+# endif
+/* If sizeof(int) == 2, then ((1 << 15) - 1) overflows.  */
+# define RE_DUP_MAX (0x7fff)
 #endif
-#define RE_DUP_MAX ((1 << 15) - 1)
 
 
 /* POSIX `cflags' bits (i.e., information for `regcomp').  */
@@ -240,18 +301,26 @@
 /* Like REG_NOTBOL, except for the end-of-line.  */
 #define REG_NOTEOL (1 << 1)
 
+/* Use PMATCH[0] to delimit the start and end of the search in the
+   buffer.  */
+#define REG_STARTEND (1 << 2)
+
 
 /* If any error codes are removed, changed, or added, update the
    `re_error_msg' table in regex.c.  */
 typedef enum
 {
+#if defined _XOPEN_SOURCE || defined __USE_XOPEN2K
+  REG_ENOSYS = -1,	/* This will never happen for this implementation.  */
+#endif
+
   REG_NOERROR = 0,	/* Success.  */
   REG_NOMATCH,		/* Didn't find a match (for regexec).  */
 
   /* POSIX regcomp return error codes.  (In the order listed in the
      standard.)  */
   REG_BADPAT,		/* Invalid pattern.  */
-  REG_ECOLLATE,		/* Not implemented.  */
+  REG_ECOLLATE,		/* Inalid collating element.  */
   REG_ECTYPE,		/* Invalid character class name.  */
   REG_EESCAPE,		/* Trailing backslash.  */
   REG_ESUBREG,		/* Invalid back reference.  */
@@ -275,85 +344,92 @@
    compiled, the `re_nsub' field is available.  All other fields are
    private to the regex routines.  */
 
+#ifndef RE_TRANSLATE_TYPE
+# define __RE_TRANSLATE_TYPE unsigned char *
+# ifdef __USE_GNU
+#  define RE_TRANSLATE_TYPE __RE_TRANSLATE_TYPE
+# endif
+#endif
+
+#ifdef __USE_GNU
+# define __REPB_PREFIX(name) name
+#else
+# define __REPB_PREFIX(name) __##name
+#endif
+
 struct re_pattern_buffer
 {
-/* [[[begin pattern_buffer]]] */
-	/* Space that holds the compiled pattern.  It is declared as
-	  `unsigned char *' because its elements are
-	   sometimes used as array indexes.  */
-  unsigned char *buffer;
+  /* Space that holds the compiled pattern.  It is declared as
+     `unsigned char *' because its elements are sometimes used as
+     array indexes.  */
+  unsigned char *__REPB_PREFIX(buffer);
 
-	/* Number of bytes to which `buffer' points.  */
-  unsigned long allocated;
+  /* Number of bytes to which `buffer' points.  */
+  unsigned long int __REPB_PREFIX(allocated);
 
-	/* Number of bytes actually used in `buffer'.  */
-  unsigned long used;
+  /* Number of bytes actually used in `buffer'.  */
+  unsigned long int __REPB_PREFIX(used);
 
-	/* Syntax setting with which the pattern was compiled.  */
-  reg_syntax_t syntax;
+  /* Syntax setting with which the pattern was compiled.  */
+  reg_syntax_t __REPB_PREFIX(syntax);
 
-	/* Pointer to a fastmap, if any, otherwise zero.  re_search uses
-	   the fastmap, if there is one, to skip over impossible
-	   starting points for matches.  */
-  char *fastmap;
+  /* Pointer to a fastmap, if any, otherwise zero.  re_search uses the
+     fastmap, if there is one, to skip over impossible starting points
+     for matches.  */
+  char *__REPB_PREFIX(fastmap);
 
-	/* Either a translate table to apply to all characters before
-	   comparing them, or zero for no translation.  The translation
-	   is applied to a pattern when it is compiled and to a string
-	   when it is matched.  */
-  char *translate;
+  /* Either a translate table to apply to all characters before
+     comparing them, or zero for no translation.  The translation is
+     applied to a pattern when it is compiled and to a string when it
+     is matched.  */
+  __RE_TRANSLATE_TYPE __REPB_PREFIX(translate);
 
-	/* Number of subexpressions found by the compiler.  */
+  /* Number of subexpressions found by the compiler.  */
   size_t re_nsub;
 
-	/* Zero if this pattern cannot match the empty string, one else.
-	   Well, in truth it's used only in `re_search_2', to see
-	   whether or not we should use the fastmap, so we don't set
-	   this absolutely perfectly; see `re_compile_fastmap' (the
-	   `duplicate' case).  */
-  unsigned can_be_null : 1;
+  /* Zero if this pattern cannot match the empty string, one else.
+     Well, in truth it's used only in `re_search_2', to see whether or
+     not we should use the fastmap, so we don't set this absolutely
+     perfectly; see `re_compile_fastmap' (the `duplicate' case).  */
+  unsigned __REPB_PREFIX(can_be_null) : 1;
 
-	/* If REGS_UNALLOCATED, allocate space in the `regs' structure
-	     for `max (RE_NREGS, re_nsub + 1)' groups.
-	   If REGS_REALLOCATE, reallocate space if necessary.
-	   If REGS_FIXED, use what's there.  */
-#define REGS_UNALLOCATED 0
-#define REGS_REALLOCATE 1
-#define REGS_FIXED 2
-  unsigned regs_allocated : 2;
+  /* If REGS_UNALLOCATED, allocate space in the `regs' structure
+     for `max (RE_NREGS, re_nsub + 1)' groups.
+     If REGS_REALLOCATE, reallocate space if necessary.
+     If REGS_FIXED, use what's there.  */
+#ifdef __USE_GNU
+# define REGS_UNALLOCATED 0
+# define REGS_REALLOCATE 1
+# define REGS_FIXED 2
+#endif
+  unsigned __REPB_PREFIX(regs_allocated) : 2;
 
-	/* Set to zero when `regex_compile' compiles a pattern; set to one
-	   by `re_compile_fastmap' if it updates the fastmap.  */
-  unsigned fastmap_accurate : 1;
+  /* Set to zero when `regex_compile' compiles a pattern; set to one
+     by `re_compile_fastmap' if it updates the fastmap.  */
+  unsigned __REPB_PREFIX(fastmap_accurate) : 1;
 
-	/* If set, `re_match_2' does not return information about
-	   subexpressions.  */
-  unsigned no_sub : 1;
+  /* If set, `re_match_2' does not return information about
+     subexpressions.  */
+  unsigned __REPB_PREFIX(no_sub) : 1;
 
-	/* If set, a beginning-of-line anchor doesn't match at the
-	   beginning of the string.  */
-  unsigned not_bol : 1;
+  /* If set, a beginning-of-line anchor doesn't match at the beginning
+     of the string.  */
+  unsigned __REPB_PREFIX(not_bol) : 1;
 
-	/* Similarly for an end-of-line anchor.  */
-  unsigned not_eol : 1;
+  /* Similarly for an end-of-line anchor.  */
+  unsigned __REPB_PREFIX(not_eol) : 1;
 
-	/* If true, an anchor at a newline matches.  */
-  unsigned newline_anchor : 1;
-
-/* [[[end pattern_buffer]]] */
+  /* If true, an anchor at a newline matches.  */
+  unsigned __REPB_PREFIX(newline_anchor) : 1;
 };
 
 typedef struct re_pattern_buffer regex_t;
-
-
-/* search.c (search_buffer) in Emacs needs this one opcode value.  It is
-   defined both in `regex.c' and here.  */
-#define RE_EXACTN_VALUE 1
 
 /* Type for byte offsets within the string.  POSIX mandates this.  */
 typedef int regoff_t;
 
 
+#ifdef __USE_GNU
 /* This is the structure we store register match data in.  See
    regex.texinfo for a full description of what registers match.  */
 struct re_registers
@@ -367,8 +443,9 @@
 /* If `regs_allocated' is REGS_UNALLOCATED in the pattern buffer,
    `re_match_2' returns information about at least this many registers
    the first time a `regs' structure is passed.  */
-#ifndef RE_NREGS
-#define RE_NREGS 30
+# ifndef RE_NREGS
+#  define RE_NREGS 30
+# endif
 #endif
 
 
@@ -383,38 +460,22 @@
 
 /* Declarations for routines.  */
 
-/* To avoid duplicating every routine declaration -- once with a
-   prototype (if we are ANSI), and once without (if we aren't) -- we
-   use the following macro to declare argument types.  This
-   unfortunately clutters up the declarations a bit, but I think it's
-   worth it.  */
-
-#if __STDC__
-
-#define _RE_ARGS(args) args
-
-#else /* not __STDC__ */
-
-#define _RE_ARGS(args) ()
-
-#endif /* not __STDC__ */
-
+#ifdef __USE_GNU
 /* Sets the current default syntax to SYNTAX, and return the old syntax.
    You can also simply assign to the `re_syntax_options' variable.  */
-extern reg_syntax_t re_set_syntax _RE_ARGS ((reg_syntax_t syntax));
+extern reg_syntax_t re_set_syntax (reg_syntax_t __syntax);
 
 /* Compile the regular expression PATTERN, with length LENGTH
    and syntax given by the global `re_syntax_options', into the buffer
    BUFFER.  Return NULL if successful, and an error string if not.  */
-extern const char *re_compile_pattern
-  _RE_ARGS ((const char *pattern, int length,
-	     struct re_pattern_buffer *buffer));
+extern const char *re_compile_pattern (const char *__pattern, size_t __length,
+				       struct re_pattern_buffer *__buffer);
 
 
 /* Compile a fastmap for the compiled pattern in BUFFER; used to
    accelerate searches.  Return 0 if successful and -2 if was an
    internal error.  */
-extern int re_compile_fastmap _RE_ARGS ((struct re_pattern_buffer *buffer));
+extern int re_compile_fastmap (struct re_pattern_buffer *__buffer);
 
 
 /* Search in the string STRING (with length LENGTH) for the pattern
@@ -422,31 +483,30 @@
    characters.  Return the starting position of the match, -1 for no
    match, or -2 for an internal error.  Also return register
    information in REGS (if REGS and BUFFER->no_sub are nonzero).  */
-extern int re_search
-  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string,
-	    int length, int start, int range, struct re_registers *regs));
+extern int re_search (struct re_pattern_buffer *__buffer, const char *__cstring,
+		      int __length, int __start, int __range,
+		      struct re_registers *__regs);
 
 
 /* Like `re_search', but search in the concatenation of STRING1 and
    STRING2.  Also, stop searching at index START + STOP.  */
-extern int re_search_2
-  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string1,
-	     int length1, const char *string2, int length2,
-	     int start, int range, struct re_registers *regs, int stop));
+extern int re_search_2 (struct re_pattern_buffer *__buffer,
+			const char *__string1, int __length1,
+			const char *__string2, int __length2, int __start,
+			int __range, struct re_registers *__regs, int __stop);
 
 
 /* Like `re_search', but return how many characters in STRING the regexp
    in BUFFER matched, starting at position START.  */
-extern int re_match
-  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string,
-	     int length, int start, struct re_registers *regs));
+extern int re_match (struct re_pattern_buffer *__buffer, const char *__cstring,
+		     int __length, int __start, struct re_registers *__regs);
 
 
 /* Relates to `re_match' as `re_search_2' relates to `re_search'.  */
-extern int re_match_2
-  _RE_ARGS ((struct re_pattern_buffer *buffer, const char *string1,
-	     int length1, const char *string2, int length2,
-	     int start, struct re_registers *regs, int stop));
+extern int re_match_2 (struct re_pattern_buffer *__buffer,
+		       const char *__string1, int __length1,
+		       const char *__string2, int __length2, int __start,
+		       struct re_registers *__regs, int __stop);
 
 
 /* Set REGS to hold NUM_REGS registers, storing them in STARTS and
@@ -461,30 +521,59 @@
    Unless this function is called, the first search or match using
    PATTERN_BUFFER will allocate its own register data, without
    freeing the old data.  */
-extern void re_set_registers
-  _RE_ARGS ((struct re_pattern_buffer *buffer, struct re_registers *regs,
-	     unsigned num_regs, regoff_t *starts, regoff_t *ends));
+extern void re_set_registers (struct re_pattern_buffer *__buffer,
+			      struct re_registers *__regs,
+			      unsigned int __num_regs,
+			      regoff_t *__starts, regoff_t *__ends);
+#endif	/* Use GNU */
 
+#if defined _REGEX_RE_COMP || (defined _LIBC && defined __USE_BSD)
+# ifndef _CRAY
 /* 4.2 bsd compatibility.  */
-extern char *re_comp _RE_ARGS ((const char *));
-extern int re_exec _RE_ARGS ((const char *));
+extern char *re_comp (const char *);
+extern int re_exec (const char *);
+# endif
+#endif
+
+/* GCC 2.95 and later have "__restrict"; C99 compilers have
+   "restrict", and "configure" may have defined "restrict".  */
+#ifndef __restrict
+# if ! (2 < __GNUC__ || (2 == __GNUC__ && 95 <= __GNUC_MINOR__))
+#  if defined restrict || 199901L <= __STDC_VERSION__
+#   define __restrict restrict
+#  else
+#   define __restrict
+#  endif
+# endif
+#endif
+/* gcc 3.1 and up support the [restrict] syntax.  */
+#ifndef __restrict_arr
+# if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1)) \
+     && !defined __GNUG__
+#  define __restrict_arr __restrict
+# else
+#  define __restrict_arr
+# endif
+#endif
 
 /* POSIX compatibility.  */
-extern int regcomp _RE_ARGS ((regex_t *preg, const char *pattern, int cflags));
-extern int regexec
-  _RE_ARGS ((const regex_t *preg, const char *string, size_t nmatch,
-	     regmatch_t pmatch[], int eflags));
-extern size_t regerror
-  _RE_ARGS ((int errcode, const regex_t *preg, char *errbuf,
-	     size_t errbuf_size));
-extern void regfree _RE_ARGS ((regex_t *preg));
+extern int regcomp (regex_t *__restrict __preg,
+		    const char *__restrict __pattern,
+		    int __cflags);
 
-#endif /* not __REGEXP_LIBRARY_H__ */
-
-/*
-Local variables:
-make-backup-files: t
-version-control: t
-trim-versions-without-asking: nil
-End:
-*/
+extern int regexec (const regex_t *__restrict __preg,
+		    const char *__restrict __cstring, size_t __nmatch,
+		    regmatch_t __pmatch[__restrict_arr],
+		    int __eflags);
+
+extern size_t regerror (int __errcode, const regex_t *__restrict __preg,
+			char *__restrict __errbuf, size_t __errbuf_size);
+
+extern void regfree (regex_t *__preg);
+
+
+#ifdef __cplusplus
+}
+#endif	/* C++ */
+
+#endif /* regex.h */