Fix format-string bugs by adding __attribute__((__format__)) in all applicable places and fixing all warnings my gcc produced. Among other things, this should fix several segfaults (including one I just ran into).

#ifndef _GNUC_H
#define _GNUC_H 1

int memicmp(const char *s1, const char *s2, int n);
int stricmp(const char *s1, const char *s2);

#endif