Xcode: resolve -Wunknown-pragmas

This is a multi-platform project and while trying to reduce amount of

Signed-off-by: Simon Rozman <simon@rozman.si>

UnitTests/unicode.cpp

@@ -9,7 +9,7 @@ using namespace std;
 #ifdef _WIN32
 using namespace Microsoft::VisualStudio::CppUnitTestFramework;
 #endif
-#ifdef __GNUC__
+#if defined(__GNUC__)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
 #endif
@@ -99,6 +99,6 @@ namespace UnitTests
 	}
 }
 
-#ifdef __GNUC__
+#if defined(__GNUC__)
 #pragma GCC diagnostic pop
 #endif