Use off_t in pack-objects/fast-import when we mean an offset

Always use an off_t value in pack-objects anytime we are dealing
with an offset to some data within a packfile.

Also fixed a minor uintmax_t that was incorrectly defined before.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/fast-import.c b/fast-import.c
index a418a17..fda5018 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -249,7 +249,7 @@
 
 /* Configured limits on output */
 static unsigned long max_depth = 10;
-static unsigned long max_packsize = (1LL << 32) - 1;
+static off_t max_packsize = (1LL << 32) - 1;
 static int force_update;
 
 /* Stats and misc. counters */
@@ -1527,7 +1527,7 @@
 {
 	while (cur_active_branches
 		&& cur_active_branches >= max_active_branches) {
-		unsigned long min_commit = ULONG_MAX;
+		uintmax_t min_commit = ULONG_MAX;
 		struct branch *e, *l = NULL, *p = NULL;
 
 		for (e = active_branches; e; e = e->active_next_branch) {