Win32 compile fix.

msvc compilers define 'inline' only for c++ code, so wrap it
with a platform independent DBUS_INLINE define in cmake
generated config.h.

bus/bus.c

@@ -1320,7 +1320,12 @@ out:
   va_end (args);
 }
 
-static inline const char *
+/* TODO: move to autotools generated config.h like done in cmake */
+#ifndef DBUS_INLINE
+#define DBUS_INLINE inline
+#endif
+
+static DBUS_INLINE const char *
 nonnull (const char *maybe_null,
          const char *if_null)
 {

cmake/config.h.cmake

@@ -253,4 +253,10 @@
 #define _dbus_verbose_C_S _dbus_verbose
 #endif 
 
+#ifdef _MSC_VER
+#define DBUS_INLINE __inline
+#else
+#define DBUS_INLINE inline
+#endif
+
 #endif  // _DBUS_CONFIG_H