> +    notmuch_bool_t ret = FALSE;
> +
> +    if (strchr(exename, '/')) {
> +	if (0 == access(exename, X_OK))
> +	    return TRUE;
> +	else
> +	    return FALSE;
> +    }
> +    
> +    c = getenv("PATH");
> +    if (c)
> +	c = talloc_strdup(NULL, c);

Is there some advantage to using the talloc_ functions here?

> +    else {

Is n needed outside this block? if not, it could be declared here (and
then I don't care about the single letter name).

> +	n = confstr(_CS_PATH, NULL, 0);

according to a glance at the man page, this might return 0 if there is
no value for _CS_PATH set?


> +
> +    tok = strtok_r(c, ":", &save);
> +    while (tok) {
same comment about block local declaration of dfd

> +	dfd = open(tok, O_DIRECTORY | O_RDONLY);

> +	tok = strtok_r(NULL, ":", &save);

not sure if it helps, but there is also strtok_len in libutil

> +done:

as a real nitpick, we have always (?) used DONE for a label.