Fix ungetwc for multi byte chars

tests/Makefile

@@ -103,6 +103,7 @@ EXPECT_NAMES=\
 	unistd/swab \
 	unistd/write \
 	waitpid \
+	wchar/fgetwc \
 	wchar/fwide \
 	wchar/mbrtowc \
 	wchar/mbsrtowcs \

tests/wchar/ungetwc.c

@@ -3,9 +3,11 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <assert.h>
- 
+#include <locale.h>
+
 int main()
 {
+   setlocale(LC_ALL, "");
    FILE *stream;
    wint_t wc;
    wint_t wc2;

tests/wchar/ungetwc.in

@@ -1 +1 @@
-123A
+123çA