More dynamic linker cleanup.

I still want to break linker_format out into its own library so we can reuse
it for malloc debugging and so forth. (There are many similar pieces of code
in bionic, but the linker's one seems to be the most complete/functional.)

Change-Id: If3721853d28937c8e821ca1d23cf200e228a409a

linker/linker_debug.h

@@ -62,10 +62,6 @@
 #if LINKER_DEBUG
 #include "linker_format.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 extern int debug_verbosity;
 #if LINKER_DEBUG_TO_LOG
 extern int format_log(int, const char *, const char *, ...);
@@ -81,10 +77,6 @@ extern int format_fd(int, const char *, ...);
     } while (0)
 #endif /* !LINKER_DEBUG_TO_LOG */
 
-#ifdef __cplusplus
-};
-#endif
-
 #else /* !LINKER_DEBUG */
 #define _PRINTVF(v,f,x...)   do {} while(0)
 #endif /* LINKER_DEBUG */