posix: remove implicit include of "fnmatch.h"

We're about to phase out our bundled fnmatch implementation as
git.git has moved to wildmatch long ago in 2014. To make it
easier to spot which files are stilll using fnmatch, remove the
implicit "fnmatch.h" include in "posix.h" and instead include it
explicitly.

src/attr_file.c

@@ -15,6 +15,7 @@
 #include "git2/tree.h"
 #include "blob.h"
 #include "index.h"
+#include "fnmatch.h"
 #include <ctype.h>
 
 static void attr_file_free(git_attr_file *file)

src/config_file.c

@@ -18,6 +18,7 @@
 #include "array.h"
 #include "config_parse.h"
 #include "config_entries.h"
+#include "fnmatch.h"
 
 #include <ctype.h>
 #include <sys/types.h>

src/describe.c

@@ -14,12 +14,13 @@
 
 #include "commit.h"
 #include "commit_list.h"
+#include "fnmatch.h"
 #include "oidmap.h"
 #include "refs.h"
+#include "repository.h"
 #include "revwalk.h"
 #include "tag.h"
 #include "vector.h"
-#include "repository.h"
 
 /* Ported from https://github.com/git/git/blob/89dde7882f71f846ccd0359756d27bebc31108de/builtin/describe.c */
 

src/pathspec.c

@@ -16,6 +16,7 @@
 #include "index.h"
 #include "bitvec.h"
 #include "diff.h"
+#include "fnmatch.h"
 
 /* what is the common non-wildcard prefix for all items in the pathspec */
 char *git_pathspec_prefix(const git_strarray *pathspec)

src/posix.h

@@ -11,7 +11,6 @@
 
 #include <fcntl.h>
 #include <time.h>
-#include "fnmatch.h"
 
 /* stat: file mode type testing macros */
 #ifndef S_IFGITLINK

src/refdb_fs.c

@@ -18,6 +18,7 @@
 #include "iterator.h"
 #include "sortedcache.h"
 #include "signature.h"
+#include "fnmatch.h"
 
 #include <git2/tag.h>
 #include <git2/object.h>

src/refspec.c

@@ -10,7 +10,7 @@
 #include "git2/errors.h"
 
 #include "util.h"
-#include "posix.h"
+#include "fnmatch.h"
 #include "refs.h"
 #include "vector.h"
 

src/status.c

@@ -16,6 +16,7 @@
 #include "repository.h"
 #include "ignore.h"
 #include "index.h"
+#include "fnmatch.h"
 
 #include "git2/diff.h"
 #include "diff.h"

src/tag.c

@@ -8,6 +8,7 @@
 #include "tag.h"
 
 #include "commit.h"
+#include "fnmatch.h"
 #include "signature.h"
 #include "message.h"
 #include "git2/object.h"

tests/describe/describe_helpers.c

 #include "describe_helpers.h"
 
+#include "fnmatch.h"
+
 void assert_describe(
 	const char *expected_output,
 	const char *revparse_spec,