Remove extra 'extern "C"' gibberish. Just depend on #ifdef __cplusplus to...

Remove extra 'extern "C"' gibberish.  Just depend on #ifdef __cplusplus to know whether to put it in.

src/winjunk.h

@@ -32,10 +32,8 @@ extern "C" {
 #undef ntohl
 #define htonl(x)  my_htonl(x)
 #define ntohl(x)  my_ntohl(x)
-extern "C" {
-  extern unsigned int my_htonl(unsigned int v);
-  extern unsigned int my_ntohl(unsigned int v);
-};
+extern unsigned int my_htonl(unsigned int v);
+extern unsigned int my_ntohl(unsigned int v);
 
 #ifndef HAVE_STRCASECMP
   extern int strcasecmp(const char *s1, const char *s2);