http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47032
--- Comment #3 from Steve Kargl <sgk at troutmask dot apl.washington.edu> 2010-12-21 18:37:21 UTC --- On Tue, Dec 21, 2010 at 05:07:53PM +0000, dje at gcc dot gnu.org wrote: > This is an interaction / assumption problem between the target (AIX) and > libgfortran. libgfortran previously built with GCC 4.4 s, this is a > regression > because libgfortran is relying on more OS features without providing an > alternative. And disabling all long double support (which works in G++) or > disabling libgfortran on AIX because of this issue seems like a bad options. > libgfortran/configure.ac has lines of the form (note I wrapped the line) AC_CHECK_LIB([m],[copysignl],[AC_DEFINE([HAVE_COPYSIGNL],[1],\ [libm includes copysignl])]) So, configure is already checking if libm contains the the "long double functions". The problem appears to be that AC_CHECK_LIB is a compile only test, and these tests appear to pass on AIX. AIX rquires a link time test to either unseti, e.g., HAVE_COPYSIGNL or configure in general should do a link time tests instead of a compile time tests to ensure the HAVE_* macros are unset.
