mesa: drop CLOCK_MONOTONIC_RAW workaround; bump relibc pointer

relibc now defines a distinct CLOCK_MONOTONIC_RAW on Redox, so the recipe's
-DCLOCK_MONOTONIC_RAW=(CLOCK_MONOTONIC+1000) c_arg override (which conflicted
with the header and only existed because relibc lacked the constant) is no
longer needed and is removed.

local/recipes/libs/mesa/recipe.toml

@@ -142,7 +142,7 @@ cookbook_meson \
     -Dplatforms=wayland,redox \
     -Degl-native-platform=redox \
     -Dshader-cache=disabled \
-    -Dc_args="['-include','alloca.h','-DCLOCK_MONOTONIC_RAW=(CLOCK_MONOTONIC+1000)','-Wno-error=implicit-function-declaration','-Wno-error=missing-prototypes','-Wno-error=return-type','-Wno-error=empty-body','-Wno-error=incompatible-pointer-types','-Wno-error=int-conversion','-Wno-error=format','-Wno-error','-std=gnu11','-Dstatic_assert=_Static_assert']" \
+    -Dc_args="['-include','alloca.h','-Wno-error=implicit-function-declaration','-Wno-error=missing-prototypes','-Wno-error=return-type','-Wno-error=empty-body','-Wno-error=incompatible-pointer-types','-Wno-error=int-conversion','-Wno-error=format','-Wno-error','-std=gnu11','-Dstatic_assert=_Static_assert']" \
     -Dcpp_args="['-include','alloca.h','-Wno-error=implicit-function-declaration','-Wno-error=missing-prototypes','-Wno-error=return-type','-Wno-error=empty-body','-Wno-error=incompatible-pointer-types','-Wno-error=int-conversion','-Wno-error=format','-Wno-error']" \
     -Dvulkan-drivers=intel,amd,swrast \
     -Dshared-glapi=enabled