Cross-compilation fails for Ghostscript 09.05

[John Darrington]

During some test builds with the GUIX system, it became apparent that,
for a number of reasons, Ghostscript cannot be cross-compiled like other GNU 
software.

The main issue, is that much of configure.ac seems to be using unusual 
constructs which
have not been designed for cross builds.  When looking at possible 
improvements, I saw this
comment:

        # We MUST NOT use PKG_CHECK_MODULES since it is a) not a standard
        # autoconf macro and b) requires pkg-config on the system, which is
        # NOT standard on ANY OS, including Linux!

I think this based on several misunderstandings:

1.  Although the PKG_CHECK_MODULES is not a "standard" macro, it is shipped in 
the pkg.m4
    file with the pkg-config tool which is common on most GNU/Linux OSes today.

2.  In fact, the PKG_CHECK_MODULES macro DOES NOT require pkg-config to be on 
the system
    at the time the macro is processed by Autoconf.  It DOES require pkg-config 
to be present
    when the resulting ./configure script is run by the user, but this is also 
true for the 
    code which is currently in configure.ac too.

3.  Neither the PKG_CHECK_MODULES macro, nor the pkg.m4 file is ever required 
to be present
    on the user's system; only that of the Ghostscript maintainers.  It is not 
required
    in order to build or configure Ghostscript; only to bootstrap it before 
making a release.
    Using PKG_CHECK_MODULES would not add any dependencies for users.


In view of this, I think that the work-arounds to avoid PKG_CHECK_MODULES are 
doing more
harm than good.   Although, I personally, am not a big fan of pkg-config, I 
think that if
it is going to be used, then it should be used in the most standard way.  
Alternatively
one could avoid pkg-config altogether and use Autoconf's AC_SEARCH_LIBS et al. 
macros, but
I think the ghostscript use case is slightly more complex than normal and this 
would not be
altogether straightforward.


Other reasons preventing cross compiling, seem to include the use of hand 
crafted macros
to test for endianess (recent autoconf has a reliable macro to do this) and a 
non-standard variable to represent the native compiler (instead of the standard 
CC_FOR_BUILD variable).


Would the Ghostscript maintainer accept a patch fixing these issues?

Regards,


John



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