Do most compilers out there really support decl-after-stmt (not likely?!),
In compiling the binaries for TeX Live, where we try to use fairly old compilers and systems, the only platform which had problems with decl-after-stmt was v5 of the IBM C compiler for AIX 4.3. There are various reasons why the person who does those builds doesn't want to use gcc, but for GNU packages, it seems like we could reasonably ask people to use gcc instead of IBM C. On the other hand, I thought I remembered seeing some previous mail about not requiring C99 in general. So we consider decl-after-stmt an exception to this?