Fix mingw build

https://github.com/Hamlib/Hamlib/issues/1478

include/hamlib/rig.h

@@ -52,7 +52,7 @@
 #endif
 
 #if __TIMESIZE != 64
-#warn TIMESIZE != 64 -- Please report your OS system to hamlib-developer@lists.sourceforge.net
+#warning TIMESIZE != 64 -- Please report your OS system to hamlib-developer@lists.sourceforge.net
 #endif
 
 // For MSVC install the NUGet pthread package