Re: [Qemu-devel] [Qemu-ppc] [PATCH] PPC: Fail configure when libfdt is not available

[David Gibson <david@gibson.dropbear.id.au>]

On Thu, Oct 20, 2011 at 08:35:45PM +0200, Gerd Hoffmann wrote:
>   Hi,
> 
> > If there are build problems with libfdt on any platform let me know
> > about them.  I would like it to build clean as widely as possible, but
> > I don't have that great a diversity of build environments, so I have
> > to reply on bug reports.
> 
> Fails to build on RHEL-5:
> 
>          CC convert-dtsv0-lexer.lex.o
> cc1: warnings being treated as errors
> convert-dtsv0-lexer.lex.c:693: warning: no previous prototype for ‘yylex’
> make: *** [convert-dtsv0-lexer.lex.o] Error 1

This one I can work around, but there's probably not much point because...

> Removing -Werror from the Makefile gets me a bit further:
> 
>          CC dtc-lexer.lex.o
> dtc-lexer.lex.c:683: warning: no previous prototype for ‘yylex’
> dtc-lexer.l: In function ‘push_input_file’:
> dtc-lexer.l:192: warning: implicit declaration of function
> ‘yypush_buffer_state’
> dtc-lexer.l:192: warning: nested extern declaration of ‘yypush_buffer_state’
> dtc-lexer.l: In function ‘pop_input_file’:
> dtc-lexer.l:201: warning: implicit declaration of function
> ‘yypop_buffer_state’
> dtc-lexer.l:201: warning: nested extern declaration of ‘yypop_buffer_state’
>          CC dtc-parser.tab.o
>          LD dtc
> dtc-lexer.lex.o: In function `push_input_file':
> /home/buildbot/git/dtc/dtc-lexer.l:192: undefined reference to
> `yypush_buffer_state'
> dtc-lexer.lex.o: In function `pop_input_file':
> /home/buildbot/git/dtc/dtc-lexer.l:201: undefined reference to
> `yypop_buffer_state'
> collect2: ld returned 1 exit status
> make: *** [dtc] Error 1

...this is harder.  I do rely fairly heavily on the lex multiple input
buffer support for processing includes.  I'm not sure when that went
in, but obviously after flex 2.5.4.

I could rewrite to not rely on the flex stuff and do it myself, but it
would be non-trivial, so I'm afraid that fix won't happen particularly
soon.

> I guess the flex version shipped with RHEL-5 is too old.
> 
> $ rpm -qf $(which lex)
> flex-2.5.4a-41.fc6

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson