[PATCH] builtin/gc: improve total_ram calculation for HAVE_BSD_SYSCTL

["Carlo Marcelo Arenas Belón" <carenas@gmail.com>]

In BSD systems other than macOS, since 9806f5a7bf (gc --auto:
exclude base pack if not enough mem to "repack -ad", 2018-04-15),
sysctl() use HW_PHYSMEM with the wrong size for the target.

Use the correct type for physical_memory on each option and make
sure it is initialized, so it is safe to use even if sysctl() fails.

While at it, add a cast to the returned value for consistency.

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
---
 builtin/gc.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/builtin/gc.c b/builtin/gc.c
index 845876ff02..3b2ca99af9 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -539,21 +539,25 @@ static uint64_t total_ram(void)
 		return total;
 	}
 #elif defined(HAVE_BSD_SYSCTL) && (defined(HW_MEMSIZE) || defined(HW_PHYSMEM) || defined(HW_PHYSMEM64))
-	int64_t physical_memory;
 	int mib[2];
 	size_t length;
-
-	mib[0] = CTL_HW;
 # if defined(HW_MEMSIZE)
+	int64_t physical_memory = 0;
+
 	mib[1] = HW_MEMSIZE;
 # elif defined(HW_PHYSMEM64)
+	int64_t physical_memory = 0;
+
 	mib[1] = HW_PHYSMEM64;
 # else
+	int physical_memory = 0;
+
 	mib[1] = HW_PHYSMEM;
 # endif
-	length = sizeof(int64_t);
+	mib[0] = CTL_HW;
+	length = sizeof(physical_memory);
 	if (!sysctl(mib, 2, &physical_memory, &length, NULL, 0))
-		return physical_memory;
+		return (uint64_t)physical_memory;
 #elif defined(GIT_WINDOWS_NATIVE)
 	MEMORYSTATUSEX memInfo;
 
-- 
2.50.0.147.gafe0d4ec5b