iOS >= 10.0 silence GLes deprecation warnings

Xcode/SDL/SDL.xcodeproj/project.pbxproj

@@ -9387,6 +9387,7 @@
 			buildSettings = {
 				CLANG_ENABLE_OBJC_ARC = YES;
 				CLANG_LINK_OBJC_RUNTIME = NO;
+				GCC_PREPROCESSOR_DEFINITIONS = GLES_SILENCE_DEPRECATION;
 				GCC_SYMBOLS_PRIVATE_EXTERN = YES;
 				SKIP_INSTALL = YES;
 				SUPPORTED_PLATFORMS = "iphonesimulator iphoneos";
@@ -9398,6 +9399,7 @@
 			buildSettings = {
 				CLANG_ENABLE_OBJC_ARC = YES;
 				CLANG_LINK_OBJC_RUNTIME = NO;
+				GCC_PREPROCESSOR_DEFINITIONS = GLES_SILENCE_DEPRECATION;
 				GCC_SYMBOLS_PRIVATE_EXTERN = YES;
 				SKIP_INSTALL = YES;
 				SUPPORTED_PLATFORMS = "iphonesimulator iphoneos";