I've attached a patch to 0.6.7 configure.in which adds a test for the compiler flag
necessary to force scsh to be built as a 32-bit executable,
adding -m32 when necessary. This is specific to gcc; other suitable flags
should be added here for other compilers.
This relates to bug 2890936, and follows advice on the scsh-users list (see
following thread), it's clear that this arises because OS X 10.6 defaults
to building 64-bit executables.