Building the package with a compiler which does not support implicit function declarations currently fails: libtool: compile: gcc -DHAVE_CONFIG_H -I. -I.. -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -c css_syntax.c -fPIC -DPIC -o .libs/css_syntax.o /usr/share/bison/bison.simple: In function 'yyparse': /usr/share/bison/bison.simple:215:19: error: implicit declaration of function 'yylex' /usr/share/bison/bison.simple:573:16: note: in expansion of macro 'YYLEX' css_syntax.y:158:25: error: implicit declaration of function 'free' 158 | free($1); | ^~~~ The missing declaration of free is easy enough to fix, but supplying a proper definition of yylex is difficult because the header defining yystype (a union) cannot be included from the parser: the generated parser C code contains a separate definition of that union. Therefore, it is necessary to build the package in C89 mode.
Upstream switched to a much newer Bison version, fixing these problems: commit d3f6f2588206897ba4f2af04be8c1a01e7019284 Author: James Le Cuirot <chewi> Date: Fri Sep 16 10:09:36 2016 +0100 Updated css_syntax.c generated with Bison 3.0.4 instead of 1.35 commit 807081583ea58b07a5ff2e0659f4173492befb8a Author: James Le Cuirot <chewi> Date: Wed Sep 14 22:56:35 2016 +0100 Update css_syntax.y for use with less ancient Bison New pregenerated css_syntax.c to follow.