musl-tcc/src/ctype/islower.c

#include <ctype.h>
#undef islower

int islower(int c)
{
	return (unsigned)c-'a' < 26;
}

int __islower_l(int c, locale_t l)
{
	return islower(c);
}

weak_alias(__islower_l, islower_l);