[RFC] Quad-float support in Fortran

[Angelo Graziosi]

Up to now, I have successfully build (weekly, on Cygwin) gfortran with 
quad support following the instructions of the old thread [*], but today 
there is some problem. The following occurs on Cygwin.

Firstly, I have build gfortran trunk rev. 166026, without the quad 
patches. The result is

$ gcc-4.6 -v
Using built-in specs.
COLLECT_GCC=gcc-4.6
COLLECT_LTO_WRAPPER=/usr/local/gfortran/libexec/gcc/i686-pc-cygwin/4.6.0/lto-wrapper.exe
Target: i686-pc-cygwin
Configured with: /tmp/gcc-4.6-r166026/configure 
--prefix=/usr/local/gfortran --program-suffix=-4.6 
--enable-languages=c,c++,fortran --enable-checking=release 
--enable-threads=posix --enable-libgomp --disable-bootstrap 
--disable-libmudflap --disable-shared
Thread model: posix
gcc version 4.6.0 20101028 (experimental) (GCC)

Then I have applied the patches (rfc1.diff) and build from scratch 
(after cleaning all) using the just built compiler, i.e. configuring as

$ CC='gcc-4.6' CXX='g++-4.6' CPP='cpp-4.6' 
/tmp/gcc-4.6-r166026/configure --prefix=/usr/local/gfortran 
--program-suffix=-4.6 --enable-languages=c,c++,fortran 
--enable-checking=release --enable-threads=posix --enable-libgomp 
--disable-bootstrap --disable-libmudflap --disable-shared

but the build fails:

[...]
checking whether to build static libraries... yes
libtool.m4: error: problem compiling FC test program
checking for /tmp/gcc-4.6-r166026/Work/./gcc/gfortran 
-B/tmp/gcc-4.6-r166026/Work/./gcc/ 
-B/usr/local/gfortran/i686-pc-cygwin/bin/ 
-B/usr/local/gfortran/i686-pc-cygwin/lib/ -isystem 
/usr/local/gfortran/i686-pc-cygwin/include -isystem 
/usr/local/gfortran/i686-pc-cygwin/sys-include    option to produce 
PIC... -DDLL_EXPORT
[...]
checking whether to build static libraries... yes
libtool.m4: error: problem compiling FC test program
checking for /tmp/gcc-4.6-r166026/Work/./gcc/gfortran 
-B/tmp/gcc-4.6-r166026/Work/./gcc/ 
-B/usr/local/gfortran/i686-pc-cygwin/bin/ 
-B/usr/local/gfortran/i686-pc-cygwin/lib/ -isystem 
/usr/local/gfortran/i686-pc-cygwin/include -isystem 
/usr/local/gfortran/i686-pc-cygwin/sys-include    option to produce 
PIC... -DDLL_EXPORT
[...]
checking sys/loadavg.h presence... no
configure: error: GNU Fortran is not working; please report a bug in 
http://gcc.gnu.org/bugzilla, attaching 
/tmp/gcc-4.6-r166026/Work/i686-pc-cygwin/libgfortran/config.log
no
checking for sys/loadavg.h... no
checking sys/time.h usability... make[1]: *** 
[configure-target-libgfortran] Error 1
make[1]: *** Waiting for unfinished jobs....
yes
checking how to print strings... printf
[...]
Adding multilib support to Makefile in /tmp/gcc-4.6-r166026/libiberty
multidirs=
with_multisubdir=
make[1]: Leaving directory `/tmp/gcc-4.6-r166026/Work'
make: *** [all] Error 2

So, what I am missing? The *same* failure happens if I try to build with 
the current GCC in Cygwin, i.e. 4.3.4.

As you perhaps notice, with the current patches (rfc1.diff), I have 
omitted from 'configure' : --with-quad=/tmp/libquad. Is this right? 
Perhaps I haven't yet understood the new procedure to build gfortran 
with quad support...

Thanks,
Angelo.

---
[*] http://gcc.gnu.org/ml/fortran/2010-09/msg00284.html