Work around missing stat(1) command.

MinGW does not have the stat command. Use ls -l to find out the size of
a file.

t/t5300-pack-object.sh

@@ -26,6 +26,12 @@ corrupt()
 	) < $1 > $2
 }
 
+test "$no_symlinks" && {
+	stat() {
+		ls -l "$3" | tr -s ' ' ' ' | cut -d' ' -f5
+	}
+}
+
 test_expect_success \
     'setup' \
     'rm -f .git/index*