misc: fix building with gcc

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

meson.build

@@ -59,6 +59,14 @@ if get_option('warning_level') != '0'
             'sign-compare', 'type-limits', 'uninitialized', 'shift-negative-value',
             'unused-but-set-parameter', 'unused-parameter', 'implicit-fallthrough=2',
             'no-unknown-warning-option', 'no-missing-braces', 'conversion', 'empty-body' ]
+  bad_warns_ubsan = [
+    'no-format-overflow' # see gcc bug 87884, enabling UBSAN makes gcc spit out spurious warnings
+                         # (if you saw this comment, went and checked gcc bugzilla, and found out
+                         # bug has been fixed, please open a PR to remove this).
+  ]
+  if get_option('b_sanitize').contains('undefined') and cc.get_id() == 'gcc'
+    warns = warns + bad_warns_ubsan
+  endif
   foreach w : warns
           if cc.has_argument('-W'+w)
                   add_global_arguments('-W'+w, language: 'c')

src/backend/gl/blur.c

@@ -290,6 +290,7 @@ static bool gl_blur_context_preallocate_textures(struct gl_blur_context *bctx,
 			case BACKEND_IMAGE_FORMAT_PIXMAP_HIGH: format = GL_RGBA16; break;
 			case BACKEND_IMAGE_FORMAT_PIXMAP: format = GL_RGBA8; break;
 			case BACKEND_IMAGE_FORMAT_MASK: format = GL_R8; break;
+			default: unreachable();
 			}
 			glTexImage2D(GL_TEXTURE_2D, 0, format, tex_size->width,
 			             tex_size->height, 0, GL_BGRA, GL_UNSIGNED_BYTE, NULL);

src/backend/gl/gl_common.c

@@ -803,7 +803,7 @@ static inline void gl_init_uniform_bitmask(struct gl_shader *shader) {
 		glGetActiveUniformName(shader->prog, (GLuint)i, sizeof(name), NULL, name);
 		GLint loc = glGetUniformLocation(shader->prog, name);
 		assert(loc >= 0 && loc <= UNIFORM_TEXSIZE_LOC);
-		shader->uniform_bitmask |= 1 << loc;
+		shader->uniform_bitmask |= 1U << loc;
 	}
 }