Initial pass at using int64_t instead of long long

Even on systems without C99 where long long and stdint are both
missing, we can shim stdint and point it to any compiler-specific
type (i.e long long, _int64, etc.).

Also next is constant suffixes and determining what needs to
include stdint.

src/hash/sha1/generic.h

@@ -11,7 +11,7 @@
 #include "hash/sha1.h"
 
 struct git_hash_sha1_ctx {
-	unsigned long long size;
+	uint64_t size;
 	unsigned int H[5];
 	unsigned int W[16];
 };

src/integer.h

@@ -43,10 +43,10 @@ GIT_INLINE(int) git__is_ulong(int64_t p)
 }
 
 /** @return true if p fits into the range of an int */
-GIT_INLINE(int) git__is_int(long long p)
+GIT_INLINE(int) git__is_int(int64_t p)
 {
 	int r = (int)p;
-	return p == (long long)r;
+	return p == (int64_t)r;
 }
 
 /* Use clang/gcc compiler intrinsics whenever possible */

src/khash.h

@@ -137,11 +137,7 @@ typedef unsigned int khint32_t;
 typedef unsigned long khint32_t;
 #endif
 
-#if ULONG_MAX == ULLONG_MAX
-typedef unsigned long khint64_t;
-#else
-typedef unsigned long long khint64_t;
-#endif
+typedef int64_t khint64_t;
 
 #ifndef kh_inline
 #ifdef _MSC_VER

src/win32/w32_util.h

@@ -74,7 +74,7 @@ GIT_INLINE(void) git_win32__filetime_to_timespec(
 	const FILETIME *ft,
 	struct timespec *ts)
 {
-	long long winTime = ((long long)ft->dwHighDateTime << 32) + ft->dwLowDateTime;
+	int64_t winTime = ((int64_t)ft->dwHighDateTime << 32) + ft->dwLowDateTime;
 	winTime -= 116444736000000000LL; /* Windows to Unix Epoch conversion */
 	ts->tv_sec = (time_t)(winTime / 10000000);
 #ifdef GIT_USE_NSEC
@@ -87,7 +87,7 @@ GIT_INLINE(void) git_win32__filetime_to_timespec(
 GIT_INLINE(void) git_win32__timeval_to_filetime(
 	FILETIME *ft, const struct p_timeval tv)
 {
-	long long ticks = (tv.tv_sec * 10000000LL) +
+	int64_t ticks = (tv.tv_sec * 10000000LL) +
 		(tv.tv_usec * 10LL) + 116444736000000000LL;
 
 	ft->dwHighDateTime = ((ticks >> 32) & 0xffffffffLL);