diff --git a/Foundation/include/Poco/Platform_POSIX.h b/Foundation/include/Poco/Platform_POSIX.h
index ee4b95faf..053d0dbc8 100644
--- a/Foundation/include/Poco/Platform_POSIX.h
+++ b/Foundation/include/Poco/Platform_POSIX.h
@@ -81,7 +81,7 @@
     // http://dbp-consulting.com/tutorials/SuppressingGCCWarnings.html
     // use example: GCC_DIAG_OFF(unused-variable)
     // 
-    #if ((__GNUC__ * 100) + __GNUC_MINOR__) >= 402
+    #if defined(POCO_COMPILER_GCC) && (((__GNUC__ * 100) + __GNUC_MINOR__) >= 402)
         #define GCC_DIAG_STR(s) #s
         #define GCC_DIAG_JOINSTR(x,y) GCC_DIAG_STR(x ## y)
         #define GCC_DIAG_DO_PRAGMA(x) _Pragma (#x)
diff --git a/Foundation/testsuite/src/FPETest.cpp b/Foundation/testsuite/src/FPETest.cpp
index 28c58a75e..46459cda3 100644
--- a/Foundation/testsuite/src/FPETest.cpp
+++ b/Foundation/testsuite/src/FPETest.cpp
@@ -77,11 +77,11 @@ void FPETest::testClassify()
 
 
 #if defined(__HP_aCC)
-#pragma OPTIMIZE OFF
+	#pragma OPTIMIZE OFF
 #elif defined(_MSC_VER)
-#pragma optimize("", off)
-#elif defined(__APPLE__)
-#pragma GCC optimization_level 0
+	#pragma optimize("", off)
+#elif defined(__APPLE__) && defined(POCO_COMPILER_GCC)
+	#pragma GCC optimization_level 0
 #endif
 
 
@@ -128,17 +128,17 @@ void FPETest::testFlags()
 
 
 #if defined(__HP_aCC)
-#pragma OPTIMIZE ON
+	#pragma OPTIMIZE ON
 #elif defined(_MSC_VER)
-#pragma optimize("", on)
-#elif defined(__APPLE__)
-#pragma GCC optimization_level reset
+	#pragma optimize("", on)
+#elif defined(__APPLE__) && defined(POCO_COMPILER_GCC)
+	#pragma GCC optimization_level reset
 #endif
 
 
 void FPETest::testRound()
 {
-	#if !defined(__osf__) && !defined(__VMS)
+#if !defined(__osf__) && !defined(__VMS)
 	FPE::setRoundingMode(FPE::FP_ROUND_TONEAREST);			
 	assert (FPE::getRoundingMode() == FPE::FP_ROUND_TONEAREST);
 	{
@@ -146,7 +146,7 @@ void FPETest::testRound()
 		assert (FPE::getRoundingMode() == FPE::FP_ROUND_TOWARDZERO);
 	}
 	assert (FPE::getRoundingMode() == FPE::FP_ROUND_TONEAREST);	
-	#endif
+#endif
 }