ref: a42941eefd1f29dc30efc3ba8d018c7ef4a72d28
dir: /sys/src/cmd/python/Python/strdup.c/
/* strdup() replacement (from stdwin, if you must know) */
#include "pgenheaders.h"
char *
strdup(const char *str)
{
	if (str != NULL) {
		register char *copy = malloc(strlen(str) + 1);
		if (copy != NULL)
			return strcpy(copy, str);
	}
	return NULL;
}