Provide bcfversion for textlive-biblatex to depend on

This reverts commit 826d15e2f1.

texlive-biblatex (biblatex 3.16) does not support a new BCF version
3.8 (bug #2048536).

biber.spec

@@ -2,8 +2,10 @@
 %bcond_without biber_enables_extra_test
 
 Name:           biber
+# Export $BCF_VERSION from lib/Biber/Constants.pm, bug #2048536
+%define bcfversion 3.7
 Version:        2.16
-Release:        4%{?dist}
+Release:        5%{?dist}
 Summary:        Command-line bibliographic manager, BibTeX replacement
 # bin/biber:        Artistic 2.0
 # data/texmap.xsl:  Artistic 2.0
@@ -137,25 +139,18 @@ Requires:       perl(Text::BibTeX) >= 0.88
 # Unicode::Collate::Locale version from Unicode::Collate in Build.PL
 Requires:       perl(Unicode::Collate::Locale) >= 1.29
 Requires:       perl(XML::LibXSLT)
-# Biber does not use biblatex, but it expects a compatible biblatex file format
-# (see doc/biber.tex "Compatibility Matrix"):
-#     biber | texlive-biblatex
-#     ------+-----------------
-#     1.8   | 2.8a
-#     2.1   | 3.0
-#     2.6   | 3.5, 3.6
-#     2.7   | 3.7       (bug #1401482)
-#     2.8   | 3.8
-#     2.9   | 3.9
-#     2.10  | 3.10
-#     2.11  | 3.11
-#     2.12  | 3.12
-#     2.13  | 3.13
-#     2.14  | 3.14
-# (biblatex also has minimum biber requirements). Provided that texlive-biblatex
-# package (e.g. 2020) does not RPM-export biblatex's version (e.g. 3.14) and
-# biblatex reached 3.14 version many years ago, it does not make sense to keep
-# the dependency from biber on texlive-biblatex >= 7:svn42680 here.
+# Biber does not use biblatex, but it requires a compatible version of
+# a biblatex control file (BCF) which is produced by biblatex. See @bcfversion
+# definition in /usr/share/texlive/texmf-dist/tex/latex/biblatex/biblatex.sty
+# and a corresponding $BCF_VERSION in lib/Biber/Constants.pm. Unfortunally,
+# Biber supports only one version of BCF. See "Compatibility Matrix" in
+# doc/biber.tex.
+# Because Biber does not use texlive-biblatex, Biber cannot Require it's exact
+# version. Because it is expensive to rebuild texlive, it's not good to
+# Require a specific biber version from texlive-biblatex.
+# Hence I proposed a bcfversion dependency which both packages can agree on
+# (bug #2048536).
+Provides:       bcfversion = %{bcfversion}
 # Version at least the main module
 Provides:       perl(Biber) = %{version}
 
@@ -263,6 +258,9 @@ export HARNESS_OPTIONS=j$(perl -e 'if ($ARGV[0] =~ /.*-j([0-9][0-9]*).*/) {print
 
 
 %changelog
+* Mon Jan 31 2022 Petr Pisar <ppisar@redhat.com> - 2.17-2
+- Provide bcfversion for textlive-biblatex to depend on (bug #2048536)
+
 * Wed Jul 21 2021 Fedora Release Engineering <releng@fedoraproject.org> - 2.16-4
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_35_Mass_Rebuild