[gimp-help] build: improve language filtering in Quickreference Makefile

[Jacob Boerema <jboerema src gnome org>]

commit d3b8cb95f9750f995349f752043a6bb3b2d042ad
Author: Jacob Boerema <jgboerema gmail com>
Date:   Tue Feb 22 18:17:56 2022 -0500

    build: improve language filtering in Quickreference Makefile
    
    Quickreference has a translation for pl that is not yet in our general
    translations. This pl was always filtered out.
    We also always ignored the globally set LINGUAS.
    
    Changed this to always limit building to languages set in LINGUAS if that
    variable is set.
    If it is not set then use QUICKREFERENCE_ALL_LINGUAS.
    
    (cherry picked from commit 2f9e9ed06b591930e4c7128d2df82bb189682f66)

 quickreference/Makefile.am | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
---
diff --git a/quickreference/Makefile.am b/quickreference/Makefile.am
index fbd04ef43..6d107237e 100644
--- a/quickreference/Makefile.am
+++ b/quickreference/Makefile.am
@@ -1,8 +1,7 @@
 ## Process this file with automake to produce Makefile.in
 
-ALL_LINGUAS ?= ca da de el en en_GB es fi fr hr it ja ko lt nl nn pt_BR ro ru sl sv zh_CN
 QUICKREFERENCE_ALL_LINGUAS ?= ca da de el es en fi fr it ja ko nl nn pl pt_BR ro ru sl sv zh_CN
-QUICKREFERENCE_LINGUAS = $(filter $(ALL_LINGUAS), $(QUICKREFERENCE_ALL_LINGUAS))
+QUICKREFERENCE_LINGUAS = $(if $(LINGUAS),$(filter 
$(QUICKREFERENCE_ALL_LINGUAS),$(LINGUAS)),$(QUICKREFERENCE_ALL_LINGUAS))
 
 POT_FILES = $(srcdir)/po/gimp-keys.pot