[Chicken-hackers] [PATCH] Fix problem building "git" egg

[Peter Bex]

Hi all,

We found a problem in the way ##sys#do-the-right-thing calls assq, which
was uncovered through 0a52536b7cb6b3d5a35ecc8f4c11131041ae873a and broke
the "git" egg's build:
http://salmonella-linux-x86.call-cc.org/master-debugbuild/gcc/linux/x86/2014/01/27/yesterday-diff/log2/install/git.html

The attached patch is simple, I hope it's also correct: it only calls
assq if there really is any info, otherwise just fall through.
I'm not 100% sure whether this is the correct fix, because I don't
really understand this code.  Maybe it should complain that the
extension doesn't (yet) exist, because it hasn't been installed
at that point?  In that case, the check should be pulled into the
"cond" check like so:

((and (memq id ##sys#explicit-library-modules)
      (##sys#extension-information id 'require-extension))
  => (lambda (info)
       (let ((nr (assq 'import-only info))
             (s (assq 'syntax info)))
         ...)))

Cheers,
Peter
-- 
http://www.more-magic.net

0001-Fix-issue-building-files-which-explicitly-use-units-.patch
Description: Text document