Fix MSVC warnings when building threads
diff --git a/src/thread-utils.h b/src/thread-utils.h
index e542639..20d6022 100644
--- a/src/thread-utils.h
+++ b/src/thread-utils.h
@@ -5,7 +5,11 @@
/* Common operations even if threading has been disabled */
typedef struct {
+#if defined(_MSC_VER)
+ volatile long val;
+#else
volatile int val;
+#endif
} git_atomic;
GIT_INLINE(void) git_atomic_set(git_atomic *a, int val)