Add support for EGL on linux

include/core/SkPostConfig.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkPostConfig_DEFINED
 #define SkPostConfig_DEFINED
 
@@ skipping 393 matching lines @@
 #ifndef SK_BARRIERS_PLATFORM_H
 #  if SK_HAS_COMPILER_FEATURE(thread_sanitizer)
 #    define SK_BARRIERS_PLATFORM_H "../../src/ports/SkBarriers_tsan.h"
 #  elif defined(SK_CPU_ARM32) || defined(SK_CPU_ARM64)
 #    define SK_BARRIERS_PLATFORM_H "../../src/ports/SkBarriers_arm.h"
 #  else
 #    define SK_BARRIERS_PLATFORM_H "../../src/ports/SkBarriers_x86.h"
 #  endif
 #endif
 
+//////////////////////////////////////////////////////////////////////
+
+#ifndef SK_EGL

[bsalomon, 2014/09/30 13:43:58]

I think the problem here is that there is no way for someone to say "I don't
want EGL". By using 0 and 1 they can define SK_EGL to 0 and avoid this default
because SK_EGL will be defined.

+#  if defined(SK_BUILD_FOR_ANDROID) || defined(SK_BUILD_FOR_NACL)
+#    define SK_EGL
+#  endif
+#endif
 
 //////////////////////////////////////////////////////////////////////
 
 #if defined(SK_GAMMA_EXPONENT) && defined(SK_GAMMA_SRGB)
 #  error "cannot define both SK_GAMMA_EXPONENT and SK_GAMMA_SRGB"
 #elif defined(SK_GAMMA_SRGB)
 #  define SK_GAMMA_EXPONENT (0.0f)
 #elif !defined(SK_GAMMA_EXPONENT)
 #  define SK_GAMMA_EXPONENT (2.2f)
 #endif
 
 #endif // SkPostConfig_DEFINED