unload libgl on exit, fix SDL_RWclose in progress_write()

src/progress.c

@@ -320,7 +320,7 @@ static void progress_write(SDL_RWops *file) {
 	}
 
 	free(buf);
-	SDL_RWclose(file);
+	SDL_RWclose(vfile);
 }
 
 #ifdef PROGRESS_UNLOCK_ALL

src/taiseigl.c

@@ -118,6 +118,12 @@ void load_gl_library(void) {
 #endif
 }
 
+void unload_gl_library(void) {
+#ifndef LINK_TO_LIBGL
+	SDL_GL_UnloadLibrary();
+#endif
+}
+
 void load_gl_functions(void) {
 #ifndef LINK_TO_LIBGL
 #define GLDEF(glname,tsname,typename) tsname = (typename)get_proc_address(#glname);

src/taiseigl.h

@@ -102,6 +102,7 @@ extern struct glext_s glext;
 void load_gl_library(void);
 void load_gl_functions(void);
 void check_gl_extensions(void);
+void unload_gl_library(void);
 
 #define gluPerspective tsgluPerspective
 void gluPerspective(GLdouble fovY, GLdouble aspect, GLdouble zNear, GLdouble zFar);

src/video.c

@@ -232,5 +232,6 @@ void video_init(void) {
 void video_shutdown(void) {
 	SDL_DestroyWindow(video.window);
 	SDL_GL_DeleteContext(video.glcontext);
+	unload_gl_library();
 	free(video.modes);
 }