Comment 3 for bug 512611

A bit more digging reveals the cause and sheds light on the commit log meaning:

Adding #warning "compiling bits/atomicfwd_c.h" at the top of djgpp/include/cxx/4.42/bits/atomicfwd_c.h and compiling a simple source that includes <iostream> leads to this interesting result:

c:/djgpp/bin/../lib/gcc/djgpp/4.42/../../../../include/cxx/4.42/bits/atomic_word.h:1:2: warning: #warning "compiling bits/atomicfwd_c.h"

So it seems gpp is looking for "atomic_word.h" (that is present in djgpp/include/cxx/4.42/djgpp/bits), but searching for it in more paths, it's told by DOSEMU that the file is present in djgpp/include/cxx/4.42/bits and it's given the contents of atomicfwd_c.h instead. This in turn breaks the compilation.

With dosemu r. 1999 I get instead:

c:/djgpp/bin/../lib/gcc/djgpp/4.42/../../../../include/cxx/4.42/djgpp/bits/atomic_word.h:1:2: warning: #warning "compiling djgpp/bits/atomic_word.h"

Anyway the bug would be resolved by bumping up the svn revision the dosemu package is based on.