Synch extern declaration with definition provided in __uClibc_main.c

include/errno.h

@@ -52,7 +52,7 @@ extern int errno;
 /* The full and simple forms of the name with which the program was
    invoked.  These variables are set up automatically at startup based on
    the value of ARGV[0] (this works only if you use GNU ld).  */
-extern char *program_invocation_name, *program_invocation_short_name;
+extern const char *program_invocation_name, *program_invocation_short_name;
 #endif /* __USE_GNU */
 #endif /* _ERRNO_H */