travis: add macOS meson build

v2: Simplify set of options now we have better defaults

Signed-off-by: Jon Turney <jon.turney@dronecode.org.uk>
Reviewed-by: Dylan Baker <dylan@pnwbakers.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>

.travis.yml

@@ -403,6 +403,11 @@ matrix:
         - MAKE_CHECK_COMMAND="make check"
         - DRI_LOADERS="--with-platforms=x11 --disable-egl"
       os: osx
+    - env:
+        - LABEL="macOS meson"
+        - BUILD=meson
+        - MESON_OPTIONS="-Degl=false"
+      os: osx
 
 before_install:
   - |