clients & tests: use eglGetPlatformDisplayEXT when supported

Reviewed-by: Derek Foreman <derekf@osg.samsung.com>
Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>
diff --git a/Makefile.am b/Makefile.am
index c509f6e..863adb2 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -74,6 +74,7 @@
 	shared/matrix.c					\
 	shared/matrix.h					\
 	shared/zalloc.h					\
+	shared/platform.h				\
 	src/weston-egl-ext.h
 
 nodist_weston_SOURCES =					\
@@ -166,7 +167,8 @@
 	src/timeline-object.h			\
 	shared/matrix.h				\
 	shared/config-parser.h			\
-	shared/zalloc.h
+	shared/zalloc.h				\
+	shared/platform.h
 
 if ENABLE_EGL
 module_LTLIBRARIES += gl-renderer.la