C++ modules support.

That commit should not affect the build, it only renames some fields in structs when headers are included from C++ source. #15

Xext/panoramiX.h

@@ -55,7 +55,11 @@ typedef struct {
     union {
         struct {
             char visibility;
+#ifndef __cplusplus
             char class;
+#else
+            char c_class;
+#endif
             char root;
         } win;
         struct {