Fix some "signed/unsigned mismatch" (msvc) compiler warnings

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Signed-off-by: Andreas Ericsson <ae@op5.se>

src/util.c

@@ -63,7 +63,7 @@ int git__suffixcmp(const char *str, const char *suffix)
 int git__dirname(char *dir, size_t n, char *path)
 {
 	char *s;
-	int  len;
+	size_t len;
 
 	assert(dir && n > 1);
 
@@ -89,7 +89,7 @@ int git__dirname(char *dir, size_t n, char *path)
 int git__basename(char *base, size_t n, char *path)
 {
 	char *s;
-	int  len;
+	size_t len;
 
 	assert(base && n > 1);
 

src/win32/dir.c

@@ -2,7 +2,7 @@
 
 static int init_filter(char *filter, size_t n, const char *dir)
 {
-	int len = strlen(dir);
+	size_t len = strlen(dir);
 
 	if (len+3 >= n)
 		return 0;