Android.mk: Allow building only Vulkan drivers

Android bundles ANGLE for implementing OpenGL ES and EGL on top of
Vulkan. When using ANGLE, mesa is only needed for its Vulkan drivers.

Cc: mesa-stable
Acked-by: Mauro Rossi <issor.oruam@gmail.com>
Reviewed-by: Roman Stratiienko <r.stratiienko@gmail.com>
Change-Id: I034a0af52f9216bc5f1322f584bc591c90222327
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24007>

android/mesa3d_cross.mk

@@ -88,7 +88,7 @@ MESON_GEN_NINJA := \
 	-Dgallium-drivers=$(subst $(space),$(comma),$(BOARD_MESA3D_GALLIUM_DRIVERS)) \
 	-Dvulkan-drivers=$(subst $(space),$(comma),$(subst radeon,amd,$(BOARD_MESA3D_VULKAN_DRIVERS)))   \
 	-Dgbm=enabled                                                                \
-	-Degl=enabled                                                                \
+	-Degl=$(if $(BOARD_MESA3D_GALLIUM_DRIVERS),enabled,disabled)                 \
 	-Dcpp_rtti=false                                                             \
 	-Dlmsensors=disabled                                                         \
 
@@ -288,7 +288,7 @@ $(MESON_OUT_DIR)/install/.install.timestamp: $(MESON_OUT_DIR)/.build.timestamp
 	rm -rf $(dir $@)
 	mkdir -p $(dir $@)
 	DESTDIR=$(call relative-to-absolute,$(dir $@)) $(MESON_BUILD) install
-	$(MESON_COPY_LIBGALLIUM)
+	$(if $(BOARD_MESA3D_GALLIUM_DRIVERS),$(MESON_COPY_LIBGALLIUM))
 	touch $@
 
 $($(M_TARGET_PREFIX)MESA3D_LIBGBM_BIN) $(MESA3D_GLES_BINS): $(MESON_OUT_DIR)/install/.install.timestamp