gettext.c: move get_preferred_languages() from http.c

Calling setlocale(LC_MESSAGES, ...) directly from http.c, without
including <locale.h>, was causing compilation warnings.  Move the
helper function to gettext.c that already includes the header and
where locale-related issues are handled.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

gettext.c

@@ -18,6 +18,31 @@
 #	endif
 #endif
 
+/*
+ * Guess the user's preferred languages from the value in LANGUAGE environment
+ * variable and LC_MESSAGES locale category if NO_GETTEXT is not defined.
+ *
+ * The result can be a colon-separated list like "ko:ja:en".
+ */
+const char *get_preferred_languages(void)
+{
+	const char *retval;
+
+	retval = getenv("LANGUAGE");
+	if (retval && *retval)
+		return retval;
+
+#ifndef NO_GETTEXT
+	retval = setlocale(LC_MESSAGES, NULL);
+	if (retval && *retval &&
+		strcmp(retval, "C") &&
+		strcmp(retval, "POSIX"))
+		return retval;
+#endif
+
+	return NULL;
+}
+
 #ifdef GETTEXT_POISON
 int use_gettext_poison(void)
 {

gettext.h

@@ -65,4 +65,6 @@ const char *Q_(const char *msgid, const char *plu, unsigned long n)
 /* Mark msgid for translation but do not translate it. */
 #define N_(msgid) msgid
 
+const char *get_preferred_languages(void);
+
 #endif

http.c

@@ -8,6 +8,7 @@
 #include "credential.h"
 #include "version.h"
 #include "pkt-line.h"
+#include "gettext.h"
 
 int active_requests;
 int http_is_verbose;
@@ -991,31 +992,6 @@ static void extract_content_type(struct strbuf *raw, struct strbuf *type,
 		strbuf_addstr(charset, "ISO-8859-1");
 }
 
-/*
- * Guess the user's preferred languages from the value in LANGUAGE environment
- * variable and LC_MESSAGES locale category if NO_GETTEXT is not defined.
- *
- * The result can be a colon-separated list like "ko:ja:en".
- */
-static const char *get_preferred_languages(void)
-{
-	const char *retval;
-
-	retval = getenv("LANGUAGE");
-	if (retval && *retval)
-		return retval;
-
-#ifndef NO_GETTEXT
-	retval = setlocale(LC_MESSAGES, NULL);
-	if (retval && *retval &&
-		strcmp(retval, "C") &&
-		strcmp(retval, "POSIX"))
-		return retval;
-#endif
-
-	return NULL;
-}
-
 static void write_accept_language(struct strbuf *buf)
 {
 	/*