vulkan: Only build when 'vulkan' distro flag is set

Only build with the vulkan distro flag is set.  (References to this flag
were found in the mesa recipe.)

In addition, only set the RRECOMEMND to mesa, if 'opengl' flag is set.  Mesa
required opengl distro flag to build.

(From OE-Core rev: 152b59e07aed76de158d553178a2710330bc4cc1)

Signed-off-by: Mark Hatle <mark.hatle@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-graphics/vulkan/vulkan-demos_git.bb

@@ -15,6 +15,8 @@ SRCREV = "18df00c7b4677b0889486e16977857aa987947e2"
 UPSTREAM_CHECK_GITTAGREGEX = "These are not the releases you're looking for"
 S = "${WORKDIR}/git"
 
+REQUIRED_DISTRO_FEATURES = 'vulkan'
+
 inherit cmake distro_features_check
 DEPENDS = "vulkan assimp"
 

meta/recipes-graphics/vulkan/vulkan_1.0.51.0.bb

@@ -18,6 +18,7 @@ UPSTREAM_CHECK_GITTAGREGEX = "sdk-(?P<pver>\d+(\.\d+)+)"
 
 S = "${WORKDIR}/git"
 
+REQUIRED_DISTRO_FEATURES = "vulkan"
 
 inherit cmake python3native lib_package distro_features_check
 ANY_OF_DISTRO_FEATURES = "x11 wayland"
@@ -32,4 +33,5 @@ PACKAGECONFIG ??= "${@bb.utils.contains('DISTRO_FEATURES', 'x11', 'x11', '' ,d)}
 PACKAGECONFIG[x11] = "-DBUILD_WSI_XLIB_SUPPORT=ON -DBUILD_WSI_XCB_SUPPORT=ON -DDEMOS_WSI_SELECTION=XCB, -DBUILD_WSI_XLIB_SUPPORT=OFF -DBUILD_WSI_XCB_SUPPORT=OFF -DDEMOS_WSI_SELECTION=WAYLAND, libxcb libx11 libxrandr"
 PACKAGECONFIG[wayland] = "-DBUILD_WSI_WAYLAND_SUPPORT=ON, -DBUILD_WSI_WAYLAND_SUPPORT=OFF, wayland"
 
-RRECOMMENDS_${PN} = "mesa-vulkan-drivers"
+# mesa requires opengl
+RRECOMMENDS_${PN} = "${@bb.utils.contains('DISTRO_FEATURES', 'opengl', 'mesa-vulkan-drivers', '', d)}"