treewide: rename 'EXCL_FLAG_' to 'PATTERN_FLAG_'

The first consumer of pattern-matching filenames was the
.gitignore feature. In that context, storing a list of patterns
as a 'struct exclude_list'  makes sense. However, the
sparse-checkout feature then adopted these structures and methods,
but with the opposite meaning: these patterns match the files
that should be included!

It would be clearer to rename this entire library as a "pattern
matching" library, and the callers apply exclusion/inclusion
logic accordingly based on their needs.

This commit replaces 'EXCL_FLAG_' to 'PATTERN_FLAG_' in the
names of the flags used on 'struct path_pattern'.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/dir.h b/dir.h
index 4114d6b..87eb106 100644
--- a/dir.h
+++ b/dir.h
@@ -11,10 +11,10 @@ struct dir_entry {
 	char name[FLEX_ARRAY]; /* more */
 };
 
-#define EXC_FLAG_NODIR 1
-#define EXC_FLAG_ENDSWITH 4
-#define EXC_FLAG_MUSTBEDIR 8
-#define EXC_FLAG_NEGATIVE 16
+#define PATTERN_FLAG_NODIR 1
+#define PATTERN_FLAG_ENDSWITH 4
+#define PATTERN_FLAG_MUSTBEDIR 8
+#define PATTERN_FLAG_NEGATIVE 16
 
 struct path_pattern {
 	/*
@@ -28,7 +28,7 @@ struct path_pattern {
 	int nowildcardlen;
 	const char *base;
 	int baselen;
-	unsigned flags;		/* EXC_FLAG_* */
+	unsigned flags;		/* PATTERN_FLAG_* */
 
 	/*
 	 * Counting starts from 1 for line numbers in ignore files,