configure: test whether -lresolv is needed

Check if -lresolv is needed for hstrerror; set NEEDS_RESOLV
accordingly, and substitute in config.mak.in.

Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/config.mak.in b/config.mak.in
index 7cce0c1..d0cd155 100644
--- a/config.mak.in
+++ b/config.mak.in
@@ -32,6 +32,7 @@
 NO_EXPAT=@NO_EXPAT@
 NEEDS_LIBICONV=@NEEDS_LIBICONV@
 NEEDS_SOCKET=@NEEDS_SOCKET@
+NEEDS_RESOLV=@NEEDS_RESOLV@
 NO_SYS_SELECT_H=@NO_SYS_SELECT_H@
 NO_D_INO_IN_DIRENT=@NO_D_INO_IN_DIRENT@
 NO_D_TYPE_IN_DIRENT=@NO_D_TYPE_IN_DIRENT@