Use SDL C runtime functions
diff --git a/src/video/kmsdrm/SDL_kmsdrmvideo.c b/src/video/kmsdrm/SDL_kmsdrmvideo.c
index b753542..54f623e 100644
--- a/src/video/kmsdrm/SDL_kmsdrmvideo.c
+++ b/src/video/kmsdrm/SDL_kmsdrmvideo.c
@@ -102,7 +102,7 @@
     if (folder) {
         while ((res = readdir(folder))) {
             int len = SDL_strlen(res->d_name);
-            if (len > 4 && strncmp(res->d_name, "card", 4) == 0) {
+            if (len > 4 && SDL_strncmp(res->d_name, "card", 4) == 0) {
                 devcount++;
             }
         }