On Thu, 17 Jan 2013, Thomas Schwinge wrote: > Issue 2: Though it will of course never be completely fail-safe, > candidate header files I identified to remedy this issue and to be used > in _AC_PROG_PREPROC_WORKS_IFELSE instead of limits.h are: float.h, > stdarg.h, stddef.h (though the latter might include additional files in > *BSD environments, which may be supported by glibc, so let's better not > use that one). Is using one of float.h and stdarg.h correct in this > situation, and do you want me to write an Autoconf patch to change that? > By manually modifying configure, I tested using stdarg.h, and that looks > fine.
limits.h is unsafe for such bootstrapping, as you found, because of how the GCC and glibc copies install each other. Really, for glibc bootstrapping I don't think you want to include any headers there. If $CPP is defined and nonempty, use that, otherwise use $CC -E; no testing for a "working" preprocessor is needed; we require GCC 4.3 or later for building glibc. > Issue 3: Assuming fixing Autoconf is the way to go, what do we do in > glibc until we upgrade to the respective future version of Autoconf? > Supply our own copy of _AC_PROG_PREPROC_WORKS_IFELSE (or AC_PROG_CPP)? Yes. There's already code in configure.in to do something special with _AC_INCLUDES_DEFAULT_REQUIREMENTS. -- Joseph S. Myers jos...@codesourcery.com