libepoxy: make buildable for x11-less environments / update to latest version

* Make glx part configurable by PACKAGECONFIG enabled by 'x11' distro feature
* Major upstream enhancement is using pkgconfig for egl. This should make
  those egl implementations happy that require compiler extra options for their
  egl headers.
  Example: meta-fsl-arm/imx-gpu-viv sets -DLINUX (and others) in egl.pc. These
  are mandatory for proper builds.

(From OE-Core rev: 7bbd34c0efd0f7d65edb7187abdde695e45f62e2)

Signed-off-by: Andreas Müller <schnitzeltony@googlemail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-graphics/libepoxy/libepoxy_git.bb

@@ -0,0 +1,24 @@
+SUMMARY = "OpenGL function pointer management library"
+HOMEPAGE = "https://github.com/anholt/libepoxy/"
+SECTION = "libs"
+
+LICENSE = "MIT"
+LIC_FILES_CHKSUM = "file://COPYING;md5=58ef4c80d401e07bd9ee8b6b58cf464b"
+
+
+SRC_URI = " \
+    git://github.com/anholt/libepoxy.git \
+    file://0001-select-platforms-based-on-configuration-results.patch \
+    file://0002-add-an-option-to-disable-glx-support.patch \
+"
+SRCREV="20062c25e7612cab023cdef44d3277ba1bd0b2de"
+PV = "1.2+git${SRCPV}"
+
+S = "${WORKDIR}/git"
+
+inherit autotools pkgconfig
+
+DEPENDS = "util-macros virtual/egl"
+
+PACKAGECONFIG[x11] = "--enable-glx, --disable-glx, virtual/libx11"
+PACKAGECONFIG ??= "${@bb.utils.contains('DISTRO_FEATURES', 'x11', 'x11', '', d)}"