Build fails if I set CC_FOR_BUILD

[ryandesign]

I mentioned this in #847 already but the build fails if I set CC_FOR_BUILD. Can this be fixed?

My interest at present is improving chez scheme in MacPorts. In MacPorts, CC_FOR_BUILD is sometimes set automatically, thus breaking the chez scheme build. Specifically, it is set if one of our "portgroups" (include files)—the "muniversal 1.1" portgroup—is included. I am currently trying to improve chez scheme in MacPorts so that it can be built for any architecture, and the muniversal portgroup provides the ability to configure and build separately for each architecture of a multi-architecture build, something your build system requires (a different --machine has to be specified for each architecture). There has been a request for MacPorts to always set CC_FOR_BUILD which will break the chez scheme build even without the improvements I'm working on.

[ryandesign]

For example this fixes it for me:

--- configure.orig	2024-02-05 16:52:07.000000000 -0600
+++ configure	2024-06-27 09:41:03.000000000 -0500
@@ -795,8 +795,6 @@
 
 if [ "$CC_FOR_BUILD" = "" ] ; then
     CC_FOR_BUILD="${CC} ${CFLAGS}"
-else
-    enableFrompb=no
 fi
 
 # Add automatic thread compilation flags, unless suppressed by --disable-auto-flags

but I don't know what other problem those removed lines were fixing.