Fix compilation warnings on linux

gcc doesn't like when we use snprintf to concatenate buffers that can
maybe truncate the result.

Fix that by lowering the max path size for directories only.

Not very clean but I am not sure how to fix that in a better way.

src/system.c

@@ -30,6 +30,8 @@
 #define PATH_MAX 1024
 #endif
 
+#define PATH_MAX_DIR (PATH_MAX - 128)
+
 #define USER_PASS(...) ((const void*[]){__VA_ARGS__})
 #define USER_GET(var, n) (((void**)var)[n])
 
@@ -44,7 +46,7 @@ sys_callbacks_t sys_callbacks = {};
 
 static const char *get_user_dir(void)
 {
-    static char ret[PATH_MAX] = "";
+    static char ret[PATH_MAX_DIR] = "";
     const char *home;
     if (!*ret) {
         home = getenv("XDG_CONFIG_HOME");
@@ -338,7 +340,7 @@ static bool path_exists(const char *path)
 int sys_iter_paths(int location, int options, const char *name,
                    void *arg, int (*f)(void *arg, const char *path))
 {
-    char base_dir[PATH_MAX];
+    char base_dir[PATH_MAX_DIR];
     char path[PATH_MAX];
     int r;