Switch to a 64-bit time_t everywhere except 32-bit x86.

Thus, BeOS compatibility is preserved (and there is no risk of
breaking GCC5<->GCC2 interoperation on hybrid builds.)

This commit only makes the actual change, the build fixes are
in the next commit.

headers/build/HaikuBuildCompatibility.h

@@ -300,8 +300,13 @@ typedef struct {
 #	define B_PRIdINO		B_PRId64
 #	define B_PRIiINO		B_PRIi64
 	/* time_t */
-#	define B_PRIdTIME		B_PRId32
-#	define B_PRIiTIME		B_PRIi32
+#	if defined(__i386__) && !defined(__x86_64__)
+#		define B_PRIdTIME		B_PRId32
+#		define B_PRIiTIME		B_PRIi32
+#	else
+#		define B_PRIdTIME		B_PRId64
+#		define B_PRIiTIME		B_PRIi64
+#	endif
 #endif	// !B_PRId8