Windows: Fix building of resource files when config.h isn't used.

Now CMake + Visual Studio works for building liblzma.dll.

Thanks to Markus Rickert.

src/common/common_w32res.rc

@@ -6,4 +6,5 @@
  */
 
 #include <winresrc.h>
+#ifdef HAVE_CONFIG_H
 # include "config.h"
@@ -9,4 +10,5 @@
 # include "config.h"
+#endif
 #define LZMA_H_INTERNAL
 #define LZMA_H_INTERNAL_RC
 #include "lzma/version.h"