Raise minimum FontConfig version to 2.12.0

I want to use FC_SYMBOL and this the first stable version to have it,
and our baseline has 2.13.x already.

Change-Id: I606b99190020085cdf20a52788a021543c365fca
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/155312
Tested-by: Jenkins
Reviewed-by: خالد حسني <khaled@libreoffice.org>

configure.ac

@@ -6091,7 +6091,7 @@ fi
 
 AC_SUBST(ENABLE_CUPS)
 
-libo_CHECK_SYSTEM_MODULE([fontconfig],[FONTCONFIG],[fontconfig >= 2.4.1],,system,TRUE)
+libo_CHECK_SYSTEM_MODULE([fontconfig],[FONTCONFIG],[fontconfig >= 2.12.0],,system,TRUE)
 
 dnl whether to find & fetch external tarballs?
 dnl ===================================================================

vcl/unx/generic/fontmanager/fontconfig.cxx

@@ -859,11 +859,12 @@ static void addtopattern(FcPattern *pPattern,
 
 namespace
 {
-    //Someday fontconfig will hopefully use bcp47, see fdo#19869
-    //In the meantime try something that will fit to workaround fdo#35118
+    //Someday fontconfig will hopefully use bcp47, see:
+    //https://gitlab.freedesktop.org/fontconfig/fontconfig/-/issues/50
+    //In the meantime try something that will fit to workaround, see:
+    //https://gitlab.freedesktop.org/fontconfig/fontconfig/-/issues/30
     OString mapToFontConfigLangTag(const LanguageTag &rLangTag)
     {
-#if defined(FC_VERSION) && (FC_VERSION >= 20492)
         std::shared_ptr<FcStrSet> xLangSet(FcGetLangs(), FcStrSetDestroy);
         OString sLangAttrib;
 
@@ -897,12 +898,6 @@ namespace
         }
 
         return OString();
-#else
-        OString sLangAttrib = OUStringToOString(rLangTag.getLanguageAndScript(), RTL_TEXTENCODING_UTF8).toAsciiLowerCase();
-        if (sLangAttrib.equalsIgnoreAsciiCase("pa-in"))
-            sLangAttrib = "pa";
-        return sLangAttrib;
-#endif
     }
 
     bool isEmoji(sal_uInt32 nCurrentChar)