[PATCH 1/4] mergesort.c: LLP64 compatibility, upcast unity for left shift

Visual Studio reports C4334 "was 64-bit shift intended" size mismatch
warning because of size miss-match.

Promote unity to the matching type to fit with the `&` operator.

Signed-off-by: Philip Oakley <redacted>

---
This is the same fix that René Scharfe provided in 42c456ff81
(mergesort: avoid left shift overflow, 2021-11-16)

Use size_t to match n when building the bitmask for checking whether a
rank is occupied, instead of the default signed int.
---
 mergesort.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mergesort.c b/mergesort.c
index 6216835566..bd9c6ef8ee 100644
--- a/mergesort.c
+++ b/mergesort.c

@@ -63,7 +63,7 @@ void *llist_mergesort(void *list,
 		void *next = get_next_fn(list);
 		if (next)
 			set_next_fn(list, NULL);
-		for (i = 0; n & (1 << i); i++)
+		for (i = 0; n & ((size_t)1 << i); i++)
 			list = llist_merge(ranks[i], list, get_next_fn,
 					   set_next_fn, compare_fn);
 		n++;

-- 
2.34.0.rc1.windows.1.4.ga126985b17