[Swig-devel] Guile autoconf

[William S F. <ws...@fu...>]

Geert and another guile folk,

pkg-config is now used to configure guile. I've found that pkg-config 
causes problems on all the non-linux machines I've tried to configure 
on. It prevents configure from completing altogether whether or not 
guile is installed. This is because even though pkg-config is installed, 
the autoconf macros we use in configure.ac are only provided by later 
versions of pkg-config - in the pkg.m4 file. Sometimes I get this 
surprising message:

+autoconf
configure.ac:51: error: possibly undefined macro: AC_MSG_NOTICE
       If this token and others are legitimate, please use m4_pattern_allow.
       See the Autoconf documentation.

Sometimes autoconf works and then I get this when running configure 
because the macros havn't expanded:

./configure: line 9084: syntax error at line 9205: `(' unexpected

This needs fixing to warn if the pkg-config autoconf macros are missing. 
Or perhaps find a way to ship pkg.m4 with SWIG as a fallback if we are 
to use keep using pkg-config.

Some questions:
- Why was guile-config dropped? It still seems to work okay.
- Why isn't PKG_PROG_PKG_CONFIG() used instead of AC_PATH_PROG to look 
for pkg config? Surely that macro will know how to look for the 
appropriately named pkg config program. Using it (when a min version is 
given as a parameter) will also give a much more obvious error as to 
what is wrong if the autoconf macros are not available.
- Shouldn't we still be using guile-config if pkg-config does not find 
guile. It looks like it provides the same info we require and can 
probably be mapped to the same GUILExxx variables needed for the makefiles.

William