[Bug libfortran/47196] --disable-libquadmath breaks bootstrap in libgfortran (quadmath_weak.h not found)

["burnus at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47196

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
          Component|bootstrap                   |libfortran
         Resolution|                            |WONTFIX

--- Comment #1 from Tobias Burnus <burnus at gcc dot gnu.org> 2011-01-07 08:52:01 UTC ---
I would suggest that you read the libquadmath related part of
http://gcc.gnu.org/install/configure.html

If you do not want to use libquadmath in libgfortran, build with
--disable-libquadmath-support -- or supply a system version of libquadmath
library/header files. Whether libquadmath is build (as part of GCC) is
independent from whether Fortran (gfortran, libgfortran) uses libquadmath or
not. This allows for the following four combination:

a) Build libquadmath and Fortran with libquadmath-based REAL(16) support
   (default on systems where __float128 is supported)

b) Build neither libquadmath nor libquadmath-based REAL(16) support
   (obviously the default on systems lacking __float128 support;
   Other use: Save a few kilobytes by having one library less)

c) Build libquadmath but no Fortran REAL(16) support
   If one wants to save a few KiB for Fortran but wants to us libquadmath, e.g,
   with C/C++

d) Don't build libquadmath, but support libquadmath-based REAL(16) in gfortran
   Useful only if the system has already a (compatible) libquadmath
installation
   libgfortran then links "-lquadmath" but the user/builder has to make sure
that
   it is in the -I and the -L paths.