integer: use int64_t's for checks

Use int64_t internally for type visibility.

src/integer.h

@@ -8,10 +8,10 @@
 #define INCLUDE_integer_h__
 
 /** @return true if p fits into the range of a size_t */
-GIT_INLINE(int) git__is_sizet(git_off_t p)
+GIT_INLINE(int) git__is_sizet(int64_t p)
 {
 	size_t r = (size_t)p;
-	return p == (git_off_t)r;
+	return p == (int64_t)r;
 }
 
 /** @return true if p fits into the range of an ssize_t */
@@ -36,10 +36,10 @@ GIT_INLINE(int) git__is_uint32(size_t p)
 }
 
 /** @return true if p fits into the range of an unsigned long */
-GIT_INLINE(int) git__is_ulong(git_off_t p)
+GIT_INLINE(int) git__is_ulong(int64_t p)
 {
 	unsigned long r = (unsigned long)p;
-	return p == (git_off_t)r;
+	return p == (int64_t)r;
 }
 
 /** @return true if p fits into the range of an int */