Added include guards and C++ extern "C" {} constructs. Partial fix for #607253.
Bugfix candidate.
diff --git a/Mac/Include/macdefs.h b/Mac/Include/macdefs.h
index 409c253..df7d6f7 100644
--- a/Mac/Include/macdefs.h
+++ b/Mac/Include/macdefs.h
@@ -2,6 +2,8 @@
    look-alike file system access functions on the Macintosh.
    Public domain by Guido van Rossum, CWI, Amsterdam (July 1987).
 */
+#ifndef Py_MACDEFS_H
+#define Py_MACDEFS_H
 
 #include <Types.h>
 #include <Files.h>
@@ -14,6 +16,10 @@
 #include <TextUtils.h>
 #endif
 
+#ifdef __cplusplus
+	extern "C" {
+#endif
+
 /* We may be able to use a std routine in think, don't know */
 extern unsigned char *Pstring(char *);
 extern char *getbootvol(void);
@@ -33,3 +39,8 @@
 #endif
 #define EOS '\0'
 #define SEP ':'
+
+#ifdef __cplusplus
+}
+#endif
+#endif