[Change] Try to create the gen directory before creating nebulae in case

it fails.

src/nebulae.c

@@ -488,12 +488,15 @@ static int nebu_generate(void) {
   /* Warn user of what is happening. */
   loadscreen_render(0.05, "Generating Nebulae...");
 
+  /* Get resolution. */
   w = SCREEN_W;
   h = SCREEN_H;
 
+  /* Try to make the directory first if it fails. */
+  lfile_dirMakeExist("%sgen", lfile_basePath());
+
   /* Generate all the nebulae backgrounds. */
   nebu = noise_genNebulaeMap(w, h, NEBULAE_Z, 5.);
-  lfile_dirMakeExist("%sgen", lfile_basePath());
 
   /* Save each nebulae as an image. */
   for(i = 0; i < NEBULAE_Z; i++) {