Makefile & configure: add a NO_FNMATCH flag

Windows and MinGW both lack fnmatch() in their C library and needed
compat/fnmatch, but they had duplicate code for adding the compat
function, and there was no Makefile flag or configure check for
fnmatch.

Change the Makefile it so that it's now possible to compile the compat
function with a NO_FNMATCH=YesPlease flag, and add a configure probe
for it.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -68,6 +68,8 @@ all::
 #
 # Define NO_MKSTEMPS if you don't have mkstemps in the C library.
 #
+# Define NO_FNMATCH if you don't have fnmatch in the C library.
+#
 # Define NO_LIBGEN_H if you don't have libgen.h.
 #
 # Define NEEDS_LIBGEN if your libgen needs -lgen when linking
@@ -1035,6 +1037,7 @@ ifeq ($(uname_S),Windows)
 	NO_UNSETENV = YesPlease
 	NO_STRCASESTR = YesPlease
 	NO_STRLCPY = YesPlease
+	NO_FNMATCH = YesPlease
 	NO_MEMMEM = YesPlease
 	# NEEDS_LIBICONV = YesPlease
 	NO_ICONV = YesPlease
@@ -1064,8 +1067,8 @@ ifeq ($(uname_S),Windows)
 	AR = compat/vcbuild/scripts/lib.pl
 	CFLAGS =
 	BASIC_CFLAGS = -nologo -I. -I../zlib -Icompat/vcbuild -Icompat/vcbuild/include -DWIN32 -D_CONSOLE -DHAVE_STRING_H -D_CRT_SECURE_NO_WARNINGS -D_CRT_NONSTDC_NO_DEPRECATE
-	COMPAT_OBJS = compat/msvc.o compat/fnmatch/fnmatch.o compat/winansi.o compat/win32/pthread.o
-	COMPAT_CFLAGS = -D__USE_MINGW_ACCESS -DNOGDI -DHAVE_STRING_H -DHAVE_ALLOCA_H -Icompat -Icompat/fnmatch -Icompat/regex -Icompat/fnmatch -Icompat/win32 -DSTRIP_EXTENSION=\".exe\"
+	COMPAT_OBJS = compat/msvc.o compat/winansi.o compat/win32/pthread.o
+	COMPAT_CFLAGS = -D__USE_MINGW_ACCESS -DNOGDI -DHAVE_STRING_H -DHAVE_ALLOCA_H -Icompat -Icompat/regex -Icompat/win32 -DSTRIP_EXTENSION=\".exe\"
 	BASIC_LDFLAGS = -IGNORE:4217 -IGNORE:4049 -NOLOGO -SUBSYSTEM:CONSOLE -NODEFAULTLIB:MSVCRT.lib
 	EXTLIBS = advapi32.lib shell32.lib wininet.lib ws2_32.lib
 	PTHREAD_LIBS =
@@ -1089,6 +1092,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	NO_UNSETENV = YesPlease
 	NO_STRCASESTR = YesPlease
 	NO_STRLCPY = YesPlease
+	NO_FNMATCH = YesPlease
 	NO_MEMMEM = YesPlease
 	NEEDS_LIBICONV = YesPlease
 	OLD_ICONV = YesPlease
@@ -1109,10 +1113,9 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	NO_REGEX = YesPlease
 	NO_PYTHON = YesPlease
 	BLK_SHA1 = YesPlease
-	COMPAT_CFLAGS += -D__USE_MINGW_ACCESS -DNOGDI -Icompat -Icompat/fnmatch -Icompat/win32
+	COMPAT_CFLAGS += -D__USE_MINGW_ACCESS -DNOGDI -Icompat -Icompat/win32
 	COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\"
-	COMPAT_OBJS += compat/mingw.o compat/fnmatch/fnmatch.o compat/winansi.o \
-		compat/win32/pthread.o
+	COMPAT_OBJS += compat/mingw.o compat/winansi.o compat/win32/pthread.o
 	EXTLIBS += -lws2_32
 	PTHREAD_LIBS =
 	X = .exe
@@ -1319,6 +1322,11 @@ endif
 ifdef NO_STRTOULL
 	COMPAT_CFLAGS += -DNO_STRTOULL
 endif
+ifdef NO_FNMATCH
+	COMPAT_CFLAGS += -Icompat/fnmatch
+	COMPAT_CFLAGS += -DNO_FNMATCH
+	COMPAT_OBJS += compat/fnmatch/fnmatch.o
+endif
 ifdef NO_SETENV
 	COMPAT_CFLAGS += -DNO_SETENV
 	COMPAT_OBJS += compat/setenv.o

config.mak.in

@@ -46,6 +46,7 @@ NO_IPV6=@NO_IPV6@
 NO_C99_FORMAT=@NO_C99_FORMAT@
 NO_HSTRERROR=@NO_HSTRERROR@
 NO_STRCASESTR=@NO_STRCASESTR@
+NO_FNMATCH=@NO_FNMATCH@
 NO_MEMMEM=@NO_MEMMEM@
 NO_STRLCPY=@NO_STRLCPY@
 NO_UINTMAX_T=@NO_UINTMAX_T@

configure.ac

@@ -783,6 +783,12 @@ GIT_CHECK_FUNC(strcasestr,
 [NO_STRCASESTR=YesPlease])
 AC_SUBST(NO_STRCASESTR)
 #
+# Define NO_FNMATCH if you don't have fnmatch
+GIT_CHECK_FUNC(fnmatch,
+[NO_FNMATCH=],
+[NO_FNMATCH=YesPlease])
+AC_SUBST(NO_FNMATCH)
+#
 # Define NO_MEMMEM if you don't have memmem.
 GIT_CHECK_FUNC(memmem,
 [NO_MEMMEM=],