Fix uClibc build
Fixes build error with uClibc and gcc-9.3.0:
../src/gallium/drivers/lima/lima_texture.c:47:15: error: expected declaration specifiers or ‘...’ before ‘__builtin_offsetof’ 47 | static_assert(offsetof(lima_tex_desc, va) == 24, "lima_tex_desc->va offset isn't 24");
../src/egl/main/egldisplay.c: In function ‘_eglGetNativePlatformFromEnv’: ../src/egl/main/egldisplay.c:101:4: error: implicit declaration of function ‘static_assert’ [-Werror=implicit-function-declaration] 101 | static_assert(ARRAY_SIZE(egl_platforms) == _EGL_NUM_PLATFORMS,
CC: 21.3