Fix some compiler warnings

Signed-off-by: falkTX <falktx@falktx.com>

source/backend/CarlaStandalone.cpp

@@ -43,16 +43,18 @@
 
 // --------------------------------------------------------------------------------------------------------------------
 
+#ifdef USING_JUCE
 static void carla_standalone_juce_init(void);
 static void carla_standalone_juce_idle(void);
 static void carla_standalone_juce_cleanup(void);
-#define carla_juce_init carla_standalone_juce_init
-#define carla_juce_idle carla_standalone_juce_idle
-#define carla_juce_cleanup carla_standalone_juce_cleanup
-#include "utils/JUCE.cpp"
-#undef carla_juce_init
-#undef carla_juce_idle
-#undef carla_juce_cleanup
+# define carla_juce_init carla_standalone_juce_init
+# define carla_juce_idle carla_standalone_juce_idle
+# define carla_juce_cleanup carla_standalone_juce_cleanup
+# include "utils/JUCE.cpp"
+# undef carla_juce_init
+# undef carla_juce_idle
+# undef carla_juce_cleanup
+#endif
 
 // -------------------------------------------------------------------------------------------------------------------
 // Always return a valid string ptr for standalone functions

source/utils/CarlaLibUtils.hpp

@@ -81,7 +81,14 @@ Func lib_symbol(const lib_t lib, const char* const symbol) noexcept
 
     try {
 #ifdef CARLA_OS_WIN
+# if defined(__GNUC__) && (__GNUC__ >= 9)
+#  pragma GCC diagnostic push
+#  pragma GCC diagnostic ignored "-Wcast-function-type"
+# endif
         return (Func)::GetProcAddress(lib, symbol);
+# if defined(__GNUC__) && (__GNUC__ >= 9)
+#  pragma GCC diagnostic pop
+# endif
 #else
         return (Func)(uintptr_t)::dlsym(lib, symbol);
 #endif