libepoxy: make EGL support optional

This commit adds a patch to the libepoxy package to make the EGL
support optional, which allows libepoxy to build with a pure OpenGL
Mesa3D configuration (i.e without EGL/OpenGLES).

Fixes:

  http://autobuild.buildroot.net/results/88774af2845e17cab021a72c8f3171fe30b3a1ff/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/libepoxy/0002-Make-EGL-support-optional.patch

@@ -0,0 +1,200 @@
+From 0511fc56e7017209ad18d16551ccaad05de9486c Mon Sep 17 00:00:00 2001
+From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+Date: Mon, 8 May 2017 23:12:49 +0200
+Subject: [PATCH] Make EGL support optional
+
+It is perfectly possible to build Mesa3D with just OpenGL support, and
+use with GLX in X.org, without having EGL/OpenGLES support.
+
+However, libepoxy currently unconditionally requires EGL support in its
+configure.ac, which causes a build failure when Mesa3D only provides
+full OpenGL support:
+
+checking for EGL... no
+configure: error: Package requirements (egl) were not met:
+
+Package egl was not found in the pkg-config search path.
+Perhaps you should add the directory containing `egl.pc'
+to the PKG_CONFIG_PATH environment variable
+Package 'egl', required by 'world', not found
+
+This commit fixes that by:
+
+ - Adjusting the configure.ac to add a --{enable,disable}-egl option
+   handled in the exact same way as --{enable,disable}-glx
+
+ - Adjusting the meson build logic in the same way.
+
+ - Adjusting src/dispatch_common.h to define PLATFORM_HAS_EGL correctly,
+   which allows to not include any EGL related header file if EGL
+   support is not enabled.
+
+Submitted-upstream: https://github.com/anholt/libepoxy/pull/123
+Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
+---
+ configure.ac          | 33 ++++++++++++++++++++++++++++-----
+ meson.build           | 21 ++++++++++++++++++---
+ meson_options.txt     |  5 +++++
+ src/dispatch_common.h |  8 ++++----
+ 4 files changed, 55 insertions(+), 12 deletions(-)
+
+diff --git a/configure.ac b/configure.ac
+index 31b0985..2dbecd9 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -88,11 +88,35 @@ AS_CASE([$enable_glx],
+   [AC_MSG_ERROR([Invalid value "$enable_glx" for option "--enable-glx"])]
+ ])
+ 
+-# The remaining platform specific API for GL/GLES are enabled
+-# depending on the platform we're building for
++AC_ARG_ENABLE([egl],
++              [AC_HELP_STRING([--enable-egl=@<:@auto,yes,no@:>@], [Enable EGL support @<:@default=auto@:>@])],
++              [enable_egl=$enableval],
++              [enable_egl=auto])
++
++AS_CASE([$enable_egl],
++  [auto], [
++    AS_CASE([$host_os],
++            [mingw*], [build_egl=no],
++            [darwin*], [build_egl=no],
++            [android*], [build_egl=no],
++            [build_egl=yes])
++  ],
++
++  [yes], [
++    build_egl=yes
++  ],
++
++  [no], [
++    build_egl=no
++  ],
++
++  [AC_MSG_ERROR([Invalid value "$enable_egl" for option "--enable-egl"])]
++])
++
++# The remaining platform specific API are enabled depending on the
++# platform we're building for
+ AS_CASE([$host_os],
+   [mingw*], [
+-    build_egl=no
+     build_wgl=yes
+     has_znow=yes
+     # On windows, the DLL has to have all of its functions
+@@ -108,7 +132,6 @@ AS_CASE([$host_os],
+   ],
+ 
+   [darwin*], [
+-    build_egl=no
+     build_wgl=no
+     build_apple=yes
+     has_znow=no
+@@ -116,7 +139,6 @@ AS_CASE([$host_os],
+   ],
+ 
+   [
+-    build_egl=yes
+     build_wgl=no
+     has_znow=yes
+     # On platforms with dlopen, we load everything dynamically and
+@@ -131,6 +153,7 @@ AM_CONDITIONAL(BUILD_EGL, test x$build_egl = xyes)
+ if test x$build_egl = xyes; then
+     PKG_CHECK_MODULES(EGL, [egl])
+     AC_DEFINE([BUILD_EGL], [1], [build EGL tests])
++    AC_DEFINE(ENABLE_EGL, [1], [Whether EGL support is enabled])
+ fi
+ 
+ AM_CONDITIONAL(BUILD_GLX, test x$build_glx = xyes)
+diff --git a/meson.build b/meson.build
+index 5435f45..226152e 100644
+--- a/meson.build
++++ b/meson.build
+@@ -51,26 +51,41 @@ elif enable_glx == 'no'
+   build_glx = false
+ endif
+ 
++enable_egl = get_option('enable-egl')
++if enable_egl == 'auto'
++  if host_system == 'windows'
++    build_egl = false
++  elif host_system == 'darwin'
++    build_egl = false
++  elif host_system == 'android'
++    build_egl = false
++  else
++    build_egl = true
++  endif
++elif enable_egl == 'yes'
++  build_egl = true
++elif enable_egl == 'no'
++  build_egl = false
++endif
++
+ # The remaining platform specific API for GL/GLES are enabled
+ # depending on the platform we're building for
+ if host_system == 'windows'
+-  build_egl = false
+   build_apple = false
+   build_wgl = true
+   has_znow = true
+ elif host_system == 'darwin'
+-  build_egl = false
+   build_apple = true
+   build_wgl = false
+   has_znow = false
+ else
+-  build_egl = true
+   build_apple = false
+   build_wgl = false
+   has_znow = true
+ endif
+ 
+ conf.set10('ENABLE_GLX', build_glx)
++conf.set10('ENABLE_EGL', build_egl)
+ 
+ # Compiler flags, taken from the Xorg macros
+ if cc.get_id() == 'msvc'
+diff --git a/meson_options.txt b/meson_options.txt
+index 18932f5..244476a 100644
+--- a/meson_options.txt
++++ b/meson_options.txt
+@@ -6,3 +6,8 @@ option('enable-glx',
+        choices: [ 'auto', 'yes', 'no' ],
+        value: 'auto',
+        description: 'Enable GLX support')
++option('enable-egl',
++       type: 'combo',
++       choices: [ 'auto', 'yes', 'no' ],
++       value: 'auto',
++       description: 'Enable EGL support')
+diff --git a/src/dispatch_common.h b/src/dispatch_common.h
+index e3277f7..e16771f 100644
+--- a/src/dispatch_common.h
++++ b/src/dispatch_common.h
+@@ -24,19 +24,19 @@
+ #include "config.h"
+ 
+ #ifdef _WIN32
+-#define PLATFORM_HAS_EGL 0
++#define PLATFORM_HAS_EGL ENABLE_EGL
+ #define PLATFORM_HAS_GLX ENABLE_GLX
+ #define PLATFORM_HAS_WGL 1
+ #elif defined(__APPLE__)
+-#define PLATFORM_HAS_EGL 0
++#define PLATFORM_HAS_EGL ENABLE_EGL
+ #define PLATFORM_HAS_GLX ENABLE_GLX
+ #define PLATFORM_HAS_WGL 0
+ #elif defined(ANDROID)
+-#define PLATFORM_HAS_EGL 1
++#define PLATFORM_HAS_EGL ENABLE_EGL
+ #define PLATFORM_HAS_GLX 0
+ #define PLATFORM_HAS_WGL 0
+ #else
+-#define PLATFORM_HAS_EGL 1
++#define PLATFORM_HAS_EGL ENABLE_EGL
+ #define PLATFORM_HAS_GLX ENABLE_GLX
+ #define PLATFORM_HAS_WGL 0
+ #endif
+-- 
+2.7.4
+

package/libepoxy/libepoxy.mk

@@ -12,6 +12,8 @@ LIBEPOXY_INSTALL_STAGING = YES
 LIBEPOXY_DEPENDENCIES = host-pkgconf xutil_util-macros
 LIBEPOXY_LICENSE = MIT
 LIBEPOXY_LICENSE_FILES = COPYING
+# 0002-Make-EGL-support-optional.patch
+LIBEPOXY_AUTORECONF = YES
 
 ifeq ($(BR2_PACKAGE_HAS_LIBEGL),y)
 LIBEPOXY_CONF_OPTS += --enable-egl