Fix segfault when uninstalling broken backed-up symlink

Issue FS#24230. If a symlink is broken and included in the removal
process of a package, we blew up and segfaulted due to
alpm_compute_md5sum() returning NULL and then performing a strcmp()
operation.

Signed-off-by: Dan McGee <dan@archlinux.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/libalpm/remove.c b/lib/libalpm/remove.c
index 7c8a99fb..22ae2bb8 100644
--- a/lib/libalpm/remove.c
+++ b/lib/libalpm/remove.c
@@ -266,7 +266,7 @@ static void unlink_file(pmpkg_t *info, char *filename, alpm_list_t *skip_remove,
 				FREE(pkghash);
 			} else {
 				char *filehash = alpm_compute_md5sum(file);
-				int cmp = strcmp(filehash,pkghash);
+				int cmp = filehash ? strcmp(filehash, pkghash) : 0;
 				FREE(filehash);
 				FREE(pkghash);
 				if(cmp != 0) {