Hack up dcgettext to try to fix CentOS build

https://github.com/fish-shell/fish-shell/issues/645

env.cpp

@@ -357,7 +357,7 @@ static void handle_locale()
         extern int _nl_msg_cat_cntr;
         _nl_msg_cat_cntr++;
 
-        dcgettext("fish", "Changing language to English", LC_MESSAGES);
+        fish_dcgettext("fish", "Changing language to English", LC_MESSAGES);
 
         if (get_is_interactive())
         {

fallback.cpp

@@ -1141,28 +1141,33 @@ char * fish_textdomain(const char * domainname)
 
 #else
 
-char * fish_gettext(const char * msgid)
+char *fish_gettext(const char * msgid)
 {
     return (char *)msgid;
 }
 
-char * fish_bindtextdomain(const char * domainname, const char * dirname)
+char *fish_bindtextdomain(const char * domainname, const char * dirname)
 {
     return NULL;
 }
 
-char * fish_textdomain(const char * domainname)
+char *fish_textdomain(const char * domainname)
 {
     return NULL;
 }
 
 #endif
 
-#ifndef HAVE_DCGETTEXT
+#if HAVE_DCGETTEXT
 
-char * dcgettext(const char * domainname,
+char *fish_dcgettext(const char * domainname, const char * msgid, int category)
-                 const char * msgid,
+{
-                 int category)
+    return dcgettext(msgid);
+}
+
+#else
+
+char *fish_dcgettext(const char * domainname, const char * msgid, int category)
 {
     return (char *)msgid;
 }

fallback.h

@@ -389,25 +389,17 @@ int futimes(int fd, const struct timeval *times);
 
 /* autoconf may fail to detect gettext (645), so don't define a function call gettext or we'll get build errors */
 
-/** Fallback implementation of gettext. Just returns the original string. */
+/** Cover for gettext() */
 char * fish_gettext(const char * msgid);
 
-/** Fallback implementation of bindtextdomain. Does nothing. */
+/** Cover for bindtextdomain() */
 char * fish_bindtextdomain(const char * domainname, const char * dirname);
 
-/** Fallback implementation of textdomain. Does nothing. */
+/** Cover for textdomain() */
 char * fish_textdomain(const char * domainname);
 
-#ifndef HAVE_DCGETTEXT
+/* Cover for dcgettext */
-
+char * fish_dcgettext(const char * domainname, const char * msgid, int category);
-/**
-   Fallback implementation of dcgettext. Just returns the original string.
-*/
-char * dcgettext(const char * domainname,
-                 const char * msgid,
-                 int category);
-
-#endif
 
 #ifndef HAVE__NL_MSG_CAT_CNTR