Use ANSI C function definition for _mcount' and remove static'

prototype from header file.

Discussed with:	bde, maybe one year ago

lib/libc/gmon/mcount.c

@@ -65,8 +65,8 @@ void	user(void);
  * both frompcindex and frompc.  Any reasonable, modern compiler will
  * perform this optimization.
  */
-_MCOUNT_DECL(frompc, selfpc)	/* _mcount; may be static, inline, etc */
-	uintfptr_t frompc, selfpc;
+/* _mcount; may be static, inline, etc */
+_MCOUNT_DECL(uintfptr_t frompc, uintfptr_t selfpc)
 {
 #ifdef GUPROF
 	u_int delta;

sys/i386/include/profile.h

@@ -148,7 +148,6 @@ __BEGIN_DECLS
 #ifdef __GNUC__
 void	mcount(void) __asm(".mcount");
 #endif
-static void	_mcount(uintfptr_t frompc, uintfptr_t selfpc);
 __END_DECLS
 
 #endif /* _KERNEL */