Add -Wmissing-prototypes

This requires functions without a prototype definition to be static.
This allows to detect dead code, export less symbols and put shared
functions in headers.

render/gles2/texture.c

@@ -27,7 +27,7 @@ struct wlr_gles2_texture *gles2_get_texture(
 	return (struct wlr_gles2_texture *)wlr_texture;
 }
 
-struct wlr_gles2_texture *get_gles2_texture_in_context(
+static struct wlr_gles2_texture *get_gles2_texture_in_context(
 		struct wlr_texture *wlr_texture) {
 	struct wlr_gles2_texture *texture = gles2_get_texture(wlr_texture);
 	if (!wlr_egl_is_current(texture->egl)) {

render/gles2/util.c

@@ -1,38 +0,0 @@
-#include <GLES2/gl2.h>
-#include <stdbool.h>
-#include <stdlib.h>
-#include <wlr/util/log.h>
-#include "render/gles2.h"
-
-const char *gles2_strerror(GLenum err) {
-	switch (err) {
-	case GL_INVALID_ENUM:
-		return "Invalid enum";
-	case GL_INVALID_VALUE:
-		return "Invalid value";
-	case GL_INVALID_OPERATION:
-		return "Invalid operation";
-	case GL_OUT_OF_MEMORY:
-		return "Out of memory";
-	case GL_INVALID_FRAMEBUFFER_OPERATION:
-		return "Invalid framebuffer operation";
-	default:
-		return "Unknown error";
-	}
-}
-
-bool _gles2_flush_errors(const char *file, int line) {
-	GLenum err;
-	bool failure = false;
-	while ((err = glGetError()) != GL_NO_ERROR) {
-		failure = true;
-		if (err == GL_OUT_OF_MEMORY) {
-			// The OpenGL context is now undefined
-			_wlr_log(WLR_ERROR, "[%s:%d] Fatal GL error: out of memory", file, line);
-			exit(1);
-		} else {
-			_wlr_log(WLR_ERROR, "[%s:%d] GL error %d %s", file, line, err, gles2_strerror(err));
-		}
-	}
-	return failure;
-}

render/meson.build

@@ -17,7 +17,6 @@ lib_wlr_render = static_library(
 		'gles2/renderer.c',
 		'gles2/shaders.c',
 		'gles2/texture.c',
-		'gles2/util.c',
 		'wlr_renderer.c',
 		'wlr_texture.c',
 	),