ext/gettext/gettext.c: check errno after calling bindtextdomain()

Since musl's bindtextdomain() returns NULL when no directory has been
explicitly bound yet (a relatively benign situation), we need to reset
errno before the call and check it afterwards to differentiate between
a real error like ENOMEM and the harmless not-yet-bound case.

Author: orlitzky

ext/gettext/gettext.c

@@ -22,6 +22,7 @@
 
 #ifdef HAVE_LIBINTL
 
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h> /* secure_getenv() */
 #include <locale.h>
@@ -192,7 +193,15 @@ PHP_FUNCTION(bindtextdomain)
 	PHP_GETTEXT_DOMAIN_LENGTH_CHECK(1, ZSTR_LEN(domain))
 
 	if (dir == NULL) {
+		/* We need to reset errno because musl's bindtextdomain()
+		 * "fails" on one of the success paths and we need to
+		 * distinguish between a real disaster (e.g. ENOMEM)
+		 * and something harmless. */
+		errno = 0;
 		btd_result = bindtextdomain(ZSTR_VAL(domain), NULL);
+		if (errno) {
+			RETURN_FALSE;
+		}
 		if (btd_result == NULL) {
 			/* It's not POSIX compliant, but musl returns
 			 * NULL rather than an implementation-defined