5798 fexecve() needed per POSIX 2008

@@ -288,10 +288,13 @@
 extern int execle(const char *, const char *, ...);
 extern int execlp(const char *, const char *, ...);
 extern int execv(const char *, char *const *);
 extern int execve(const char *, char *const *, char *const *);
 extern int execvp(const char *, char *const *);
+#if defined(_XPG7) || !defined(_STRICT_SYMBOLS)
+extern int fexecve(int, char *const[], char *const[]);
+#endif
 extern void _exit(int)
         __NORETURN;
 /*
  * The following fattach prototype is duplicated in <stropts.h>. The
  * duplication is necessitated by XPG4.2 which requires the prototype