> My build error seems actually unrelated to encoding issues.  Working
> directory is ASCII-only, locale is UTF-8.
> 
> $ ./configure --with-pydebug
> [snip]
> $ make
> [snip]
> ranlib libpython3.2dm.a
> gcc -pthread   -Xlinker -export-dynamic -o python Modules/python.o
> libpython3.2dm.a -lpthread -ldl  -lutil   -lm Could not find platform
> dependent libraries <exec_prefix>
> Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>]
> Segmentation fault
> make: *** [sharedmods] Erreur 139

Can you retry in gdb to dump the backtrace?

Try maybe to cleanup your local copy with "make distclean".

As expected, I cannot reproduce your bug. Try to give all commands to 
reproduce the bug, and give as much information as possible.