Bug#960410: libexplain FTBFS with bison 3.6.1

[Adrian Bunk <bunk@debian.org>]

Source: libexplain
Version: 1.4.D001-9
Severity: serious
Tags: ftbfs

https://tests.reproducible-builds.org/debian/rb-pkg/unstable/amd64/libexplain.html

...
y.tab.c:152:27: error: expected identifier or '(' before numeric constant
libexplain/acl_grammar.y:128:1: note: in expansion of macro 'acl_grammar_error'
  128 | yyerror(const char *text)
      | ^~~~~~~~~~~~~~~~~
libexplain/acl_grammar.y: In function 'acl_grammar_errorf':
y.tab.c:152:27: error: called object is not a function or function pointer
libexplain/acl_grammar.y:155:5: note: in expansion of macro 'acl_grammar_error'
  155 |     yyerror(buf);
      |     ^~~~~~~~~~~~~    
libexplain/acl_grammar.y: In function 'acl_grammar_parse':
y.tab.c:152:27: error: called object is not a function or function pointer
libexplain/acl_grammar.y:470:13: note: in expansion of macro 'acl_grammar_error'
  470 |             yyerror
      |             ^~~~~~~          
y.tab.c:152:27: error: called object is not a function or function pointer
y.tab.c:1720:7: note: in expansion of macro 'acl_grammar_error'
y.tab.c:152:27: error: called object is not a function or function pointer
y.tab.c:1831:3: note: in expansion of macro 'acl_grammar_error'
At top level:
libexplain/acl_grammar.y:105:1: warning: 'result_append' defined but not used [-Wunused-function]
  105 | result_append(const char *text)
      | ^~~~~~~~~~~~~
make[1]: *** [Makefile:4037: libexplain/acl_grammar.yacc.lo] Error 1