signal.h, from glibc-devel-2.1.1-6, has this around line 60: #if defined __USE_XOPEN && !defined pid_t typedef __pid_t pid_t; # define pid_t pid_t #endif /* Unix98 */ The "#define pid_t pid_t" causes an error "macro or '#include' recursion too deep" when something tries to use it (apparently with USE_XOPEN) is defined. I noticed this when trying to build CFS (cryptographic file system). Doing a grep for "define pid_t pid_t" shows that it also happens in termios.h and unistd.h...
More things like this cause CFS compilation to break. I found more recursive pid_t defines in sys/stat.h , sys/types.h, and sys/wait.h. And, there is a similar problem with ssize_t, in unistd.h and sys/types.h. This seems to happen all over the header files with various types. Is this a glibc header problem or a compiler problem? Seems like a poorly thought out header problem even if they were assuming the compiler wouldn't recusively interpret defines...
What are the compile flags used by those programs? ANSI C certainly does not forbid #define foo foo syntax.