This note serves as a reminder which flags to use for building GCC.
For Ada support on Debian wheezy, this configure script invocation is required:
$ CC=gnatgcc ../trunk/configure --prefix=/opt/gcc-trunk \ --enable-languages=c,c++,lto,go,ada --disable-multilib \ --disable-libstdcxx-pch --enable-checking=release
Without the CC=gnatgcc part, the configure script will not find the GCC driver with Ada support. There is no separate way for setting an Ada-only compiler driver, unfortunately.
Without the Ada part, this configure script invocation works on Fedora 17 as well.
Previous workarounds for GCC's lack of knowledge of Debian's multi-arch approach (setting environment variable LIBRARY_PATH) are no longer necessary.
2012-12-28: published
2013-11-02: Removed --disable-mudflap because mudflap support was removed from the compiler. Adjusted the installation prefix.