Bug#893469: perl FTCBFS: error: unknown type name '_LIB_VERSION_TYPE'

[Niko Tyni]

On Mon, Mar 19, 2018 at 08:41:10AM +0100, Helmut Grohne wrote:
> Source: perl
> Version: 5.26.1-5
> User: helmutg at debian.org
> Usertags: rebootstrap
> 
> Hi perl maintainers,
> 
> I see that you keep updating those cross files in the debian folder.
> Thus it seems like you would still be interested in learning when cross
> building perl stops working even when I tell you without attaching a
> patch. (Sorry) 

That's absolutely fine, thanks for the report!

> | powerpc-linux-gnu-gcc -c -DPERL_CORE -D_REENTRANT -D_GNU_SOURCE -DDEBIAN -Wdate-time -D_FORTIFY_SOURCE=2 -g -O2 -fdebug-prefix-map=/build/perl-NAqo_f/perl-5.26.1=. -fstack-protector-strong -Wformat -Werror=format-security -fwrapv -fno-strict-aliasing -pipe -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -std=c89 -O2 -g -Wall -Werror=declaration-after-statement -Wextra -Wc++-compat -Wwrite-strings pp.c
> | pp.c:47:5: error: unknown type name '_LIB_VERSION_TYPE'; did you mean '__VERSION__'?
> |      _LIB_VERSION_TYPE _LIB_VERSION = _IEEE_;

> The host architecture being used seems to be irrelevant. I looked and
> couldn't figure out what is wrong here. Could it be that some configure
> result is cached wrongly somehow?

Yeah, pretty much that. Quoting Aurelien in #890242 :

  Starting with glibc 2.27, support for the "ieee" library (part of SVID
  specification) has been removed. The libieee.a library is therefore not
  shipped anymore. perl correctly detects that it is not available and
  build fine, but it introduces a small symbol change, as _LIB_VERSION is 
  provided by libieee.a.

Looks like regen-configure/U/perl/d_libm_lib_version.U probes for
_LIB_VERSION and stores the result in config.sh as 'd_libm_lib_version'.
Now that it's gone from libm and math.h, the stored config.sh files
need to be updated. I'll do that for the next upload; should be just a
matter of

 sed -i "s/d_libm_lib_version='define'/d_libm_lib_version='undef'/" debian/cross/*/config.sh.static

-- 
Niko