Wrap WIN32 #pragma warning(disable) inside push/pop

Exclude from MinGW, G++ doesn't understand these pragmas.

src/misc/pv/epicsException.h

@@ -35,8 +35,6 @@
 #define EPICSEXCEPTION_H_
 
 #ifdef _WIN32
-#pragma warning( push )
-#pragma warning(disable: 4275) // warning C4275: non dll-interface class used as base for dll-interface class (std::logic_error)
 #endif
 
 #include <stdexcept>
@@ -67,6 +65,11 @@
 #  define EXCEPT_USE_NONE
 #endif
 
+#if defined(_WIN32) && !defined(_MINGW)
+#pragma warning( push )
+#pragma warning(disable: 4275) // warning C4275: non dll-interface class used as base for dll-interface class (std::logic_error)
+#endif
+
 namespace epics { namespace pvData {
 
 
@@ -228,7 +231,7 @@ private:
     mutable std::string base_msg;
 };
 
-#ifdef _WIN32
+#if defined(_WIN32) && !defined(_MINGW)
 #pragma warning( pop )
 #endif