Quoth G. Branden Robinson:
Yes, but do look at yacc’s output, eqn.cpp. Using OpenBSD’s yacc, eqn.cpp starts with this:#include <stdlib.h> #include <string.h> #define YYBYACC 1 #define YYMAJOR 1 #define YYMINOR 9 #define YYLEX yylex() #define YYEMPTY -1 #define yyclearin (yychar=(YYEMPTY)) #define yyerrok (yyerrflag=0) #define YYRECOVERING() (yyerrflag!=0) #define YYPREFIX "yy" #line 19 "src/preproc/eqn/eqn.ypp" #ifdef HAVE_CONFIG_H #include <config.h> #endif #include <stdio.h> #include <string.h> #include <stdlib.h> #include "lib.h" #include "box.h" extern int non_empty_flag; int yylex(); void yyerror(const char *);Okay, yes, I can confirm this output and the failure. It appears to me that byacc is just not playing nicely with Autoconf here. And maybe not with other tools, since it's _assuming_ that the output will require stdlib.h and string.h. (Its own boilerplate code indeed might, but its aggression here has clear negative consequences.)
PerhapsThe alternative to yacc adding #include directives is yacc declaring the functions it uses by itself. It would be a little harder to have the yacc output not infringe on the user namespace in any way: If the parser wants to use memset and the user snippets want to define a macro called memset, what do you do? But I think that problem is a lot less imortant than what I perceive to be the actual problem:
Gnulib doesn’t play nice with others here, in prohibiting you from including standard library headers without doing something gnulib-specific, without including config.h. I think yacc is entitled to believe that its output is able to include standard library headers.
I don't see a path forward here except documenting that OpenBSD's byacc is not usable for repo builds. (Since we ship eqn.[ch]pp in distribution archives, the impact on most users sourcing their groff from GNU should be small.) What do you think?
I think the gnulib headers should be fixed, somehow. I don’t know gnulib well. I also don’t know autoconf, automake, or bison well.
The gnulib headers could just include config.h directly. I don’t know. There may be more platforms with a yacc behaving similar to OpenBSD’s yacc. And I would like to be able to uninstall bison again. But I don’t care all that much.
