Fix problems with message catalog directory

- In appimage, the message catalog is not used because there is no
  message catalog in LOCALE_INSTALL_DIR. Therefore, change to
  exepath/../share/locale instead of LOCALE_INSTALL_DIR.
- The old vim style($runtime/lang) is no longer used. Thus all relevant
  code is removed.

config/config.h.in

@@ -13,7 +13,6 @@
 #endif
 
 #define PROJECT_NAME "@PROJECT_NAME@"
-#define LOCALE_INSTALL_DIR "@CMAKE_INSTALL_FULL_LOCALEDIR@"
 
 #cmakedefine HAVE__NSGETENVIRON
 #cmakedefine HAVE_FD_CLOEXEC

src/nvim/eval.c

@@ -1890,7 +1890,7 @@ static char_u *ex_let_one(char_u *arg, typval_T *const tv,
           }
         }
         if (p != NULL) {
-          vim_setenv(name, p);
+          os_setenv(name, p, 1);
           if (STRICMP(name, "HOME") == 0) {
             init_homedir();
           } else if (didset_vim && STRICMP(name, "VIM") == 0) {

src/nvim/ex_cmds2.c

@@ -2821,10 +2821,10 @@ void ex_packadd(exarg_T *eap)
 /// ":options"
 void ex_options(exarg_T *eap)
 {
-  vim_setenv("OPTWIN_CMD", cmdmod.tab ? "tab" : "");
-  vim_setenv("OPTWIN_CMD",
-             cmdmod.tab ? "tab" :
-             (cmdmod.split & WSP_VERT) ? "vert" : "");
+  os_setenv("OPTWIN_CMD", cmdmod.tab ? "tab" : "", 1);
+  os_setenv("OPTWIN_CMD",
+            cmdmod.tab ? "tab" :
+            (cmdmod.split & WSP_VERT) ? "vert" : "", 1);
   cmd_source((char_u *)SYS_OPTWIN_FILE, NULL);
 }
 
@@ -3916,19 +3916,19 @@ void ex_language(exarg_T *eap)
       _nl_msg_cat_cntr++;
 #endif
       // Reset $LC_ALL, otherwise it would overrule everything.
-      vim_setenv("LC_ALL", "");
+      os_setenv("LC_ALL", "", 1);
 
       if (what != LC_TIME) {
         // Tell gettext() what to translate to.  It apparently doesn't
         // use the currently effective locale.
         if (what == LC_ALL) {
-          vim_setenv("LANG", (char *)name);
+          os_setenv("LANG", (char *)name, 1);
 
           // Clear $LANGUAGE because GNU gettext uses it.
-          vim_setenv("LANGUAGE", "");
+          os_setenv("LANGUAGE", "", 1);
         }
         if (what != LC_CTYPE) {
-          vim_setenv("LC_MESSAGES", (char *)name);
+          os_setenv("LC_MESSAGES", (char *)name, 1);
           set_helplang_default((char *)name);
         }
       }

src/nvim/main.c

@@ -712,22 +712,18 @@ static void init_locale(void)
   setlocale(LC_NUMERIC, "C");
 # endif
 
-# ifdef LOCALE_INSTALL_DIR    // gnu/linux standard: $prefix/share/locale
-  bindtextdomain(PROJECT_NAME, LOCALE_INSTALL_DIR);
-# else                        // old vim style: $runtime/lang
-  {
-    char_u  *p;
-
-    // expand_env() doesn't work yet, because g_chartab[] is not
-    // initialized yet, call vim_getenv() directly
-    p = (char_u *)vim_getenv("VIMRUNTIME");
-    if (p != NULL && *p != NUL) {
-      vim_snprintf((char *)NameBuff, MAXPATHL, "%s/lang", p);
-      bindtextdomain(PROJECT_NAME, (char *)NameBuff);
-    }
-    xfree(p);
+  char localepath[MAXPATHL] = { 0 };
+  char *exepath = localepath;
+  size_t exepathlen = MAXPATHL;
+  if (os_exepath(exepath, &exepathlen) != 0) {
+    path_guess_exepath(argv0 ? argv0 : "nvim", exepath, sizeof(exepath));
   }
-# endif
+  char *tail = (char *)path_tail_with_sep((char_u *)exepath);
+  *tail = NUL;
+  tail = (char *)path_tail((char_u *)exepath);
+  xstrlcpy(tail, "share/locale",
+           sizeof(localepath) - (size_t)(tail - localepath));
+  bindtextdomain(PROJECT_NAME, localepath);
   textdomain(PROJECT_NAME);
   TIME_MSG("locale set");
 }

src/nvim/option.c

@@ -2598,11 +2598,11 @@ did_set_string_option(
   } else if (varp == &p_hf) {  // 'helpfile'
     // May compute new values for $VIM and $VIMRUNTIME
     if (didset_vim) {
-      vim_setenv("VIM", "");
+      os_setenv("VIM", "", 1);
       didset_vim = false;
     }
     if (didset_vimruntime) {
-      vim_setenv("VIMRUNTIME", "");
+      os_setenv("VIMRUNTIME", "", 1);
       didset_vimruntime = false;
     }
   } else if (varp == &curwin->w_p_cc) {  // 'colorcolumn'
@@ -6744,7 +6744,7 @@ void vimrc_found(char_u *fname, char_u *envname)
       // Set $MYVIMRC to the first vimrc file found.
       p = FullName_save((char *)fname, false);
       if (p != NULL) {
-        vim_setenv((char *)envname, p);
+        os_setenv((char *)envname, p, 1);
         xfree(p);
       }
     } else {

src/nvim/os/env.c

@@ -805,10 +805,10 @@ char *vim_getenv(const char *name)
   // next time, and others can also use it (e.g. Perl).
   if (vim_path != NULL) {
     if (vimruntime) {
-      vim_setenv("VIMRUNTIME", vim_path);
+      os_setenv("VIMRUNTIME", vim_path, 1);
       didset_vimruntime = true;
     } else {
-      vim_setenv("VIM", vim_path);
+      os_setenv("VIM", vim_path, 1);
       didset_vim = true;
     }
   }
@@ -955,22 +955,6 @@ char_u * home_replace_save(buf_T *buf, char_u *src) FUNC_ATTR_NONNULL_RET
   return dst;
 }
 
-/// Vim setenv() wrapper with special handling for $VIMRUNTIME to keep the
-/// localization machinery sane.
-void vim_setenv(const char *name, const char *val)
-{
-  os_setenv(name, val, 1);
-#ifndef LOCALE_INSTALL_DIR
-  // When setting $VIMRUNTIME adjust the directory to find message
-  // translations to $VIMRUNTIME/lang.
-  if (*val != NUL && STRICMP(name, "VIMRUNTIME") == 0) {
-    char *buf = (char *)concat_str((char_u *)val, (char_u *)"/lang");
-    bindtextdomain(PROJECT_NAME, buf);
-    xfree(buf);
-  }
-#endif
-}
-
 
 /// Function given to ExpandGeneric() to obtain an environment variable name.
 char_u *get_env_name(expand_T *xp, int idx)