fix eglChooseConfig() for special attributes.

affects software renderer (emu) only.

per EGL spec:
  If EGL_MAX_PBUFFER_WIDTH, EGL_MAX_PBUFFER_HEIGHT,
  EGL_MAX_PBUFFER_PIXELS, or EGL_NATIVE_VISUAL_ID are specified
  in attrib list, then they are ignored

Change-Id: I3d5214ce896986da2f11d2eb1889afc41731eaa6
diff --git a/opengl/libagl/egl.cpp b/opengl/libagl/egl.cpp
index ba33e17..662a1fa 100644
--- a/opengl/libagl/egl.cpp
+++ b/opengl/libagl/egl.cpp
@@ -833,6 +833,9 @@
     static bool mask(GLint reqValue, GLint confValue) {
         return (confValue & reqValue) == reqValue;
     }
+    static bool ignore(GLint reqValue, GLint confValue) {
+        return true;
+    }
 };
 
 // ----------------------------------------------------------------------------
@@ -1060,11 +1063,11 @@
         { EGL_CONFIG_CAVEAT,              config_management_t::exact   },
         { EGL_CONFIG_ID,                  config_management_t::exact   },
         { EGL_LEVEL,                      config_management_t::exact   },
-        { EGL_MAX_PBUFFER_HEIGHT,         config_management_t::exact   },
-        { EGL_MAX_PBUFFER_PIXELS,         config_management_t::exact   },
-        { EGL_MAX_PBUFFER_WIDTH,          config_management_t::exact   },
+        { EGL_MAX_PBUFFER_HEIGHT,         config_management_t::ignore   },
+        { EGL_MAX_PBUFFER_PIXELS,         config_management_t::ignore   },
+        { EGL_MAX_PBUFFER_WIDTH,          config_management_t::ignore   },
         { EGL_NATIVE_RENDERABLE,          config_management_t::exact   },
-        { EGL_NATIVE_VISUAL_ID,           config_management_t::exact   },
+        { EGL_NATIVE_VISUAL_ID,           config_management_t::ignore   },
         { EGL_NATIVE_VISUAL_TYPE,         config_management_t::exact   },
         { EGL_SAMPLES,                    config_management_t::exact   },
         { EGL_SAMPLE_BUFFERS,             config_management_t::exact   },