[gimp] app: allows for empty string as language.

[Jehan <jehanp src gnome org>]

commit 5a78326589dc7a205cdf1136ef85324026d5ff04
Author: Jehan <jehan girinstud io>
Date:   Thu Jul 7 22:13:28 2022 +0200

    app: allows for empty string as language.
    
    Language detection was not working fine on Windows when the language was
    an empty string rather than NULL.

 app/language.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/app/language.c b/app/language.c
index c1623f562d..ce0406d16c 100644
--- a/app/language.c
+++ b/app/language.c
@@ -52,10 +52,10 @@ language_init (const gchar *language)
     return actual_language;
 
 #ifdef G_OS_WIN32
-  if (! language                       &&
-      g_getenv ("LANG")        == NULL &&
-      g_getenv ("LC_MESSAGES") == NULL &&
-      g_getenv ("LC_ALL")      == NULL &&
+  if ((! language || strlen (language) == 0) &&
+      g_getenv ("LANG")        == NULL       &&
+      g_getenv ("LC_MESSAGES") == NULL       &&
+      g_getenv ("LC_ALL")      == NULL       &&
       g_getenv ("LANGUAGE")    == NULL)
     {
       /* FIXME: This is a hack. gettext doesn't pick the right language