mingw: handle absolute paths in expand_user_path()

On Windows, an absolute POSIX path needs to be turned into a Windows
one.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

path.c

@@ -5,6 +5,7 @@
 #include "strbuf.h"
 #include "string-list.h"
 #include "dir.h"
+#include "exec_cmd.h"
 
 static int get_st_mode_bits(const char *path, int *mode)
 {
@@ -575,6 +576,10 @@ char *expand_user_path(const char *path)
 
 	if (path == NULL)
 		goto return_null;
+#ifdef __MINGW32__
+	if (path[0] == '/')
+		return system_path(path + 1);
+#endif
 	if (path[0] == '~') {
 		const char *first_slash = strchrnul(path, '/');
 		const char *username = path + 1;