mingw: move unlink wrapper to mingw.c

The next patch implements a workaround in case unlink fails on Windows.
Signed-off-by: NHeiko Voigt <hvoigt@hvoigt.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

compat/mingw.c

@@ -116,6 +116,14 @@ int err_win_to_posix(DWORD winerr)
 	return error;
 }
 
+#undef unlink
+int mingw_unlink(const char *pathname)
+{
+	/* read-only files cannot be removed */
+	chmod(pathname, 0666);
+	return unlink(pathname);
+}
+
 #undef open
 int mingw_open (const char *filename, int oflags, ...)
 {

compat/mingw.h

@@ -125,14 +125,6 @@ static inline int mingw_mkdir(const char *path, int mode)
 }
 #define mkdir mingw_mkdir
 
-static inline int mingw_unlink(const char *pathname)
-{
-	/* read-only files cannot be removed */
-	chmod(pathname, 0666);
-	return unlink(pathname);
-}
-#define unlink mingw_unlink
-
 #define WNOHANG 1
 pid_t waitpid(pid_t pid, int *status, unsigned options);
 
@@ -180,6 +172,9 @@ int link(const char *oldpath, const char *newpath);
  * replacements of existing functions
  */
 
+int mingw_unlink(const char *pathname);
+#define unlink mingw_unlink
+
 int mingw_open (const char *filename, int oflags, ...);
 #define open mingw_open