Fortran library finding bug GNU Autoconf Autoconf 2.61 (and others)

[Marc W. Mengel]

In the autoconf generated configure from a GNU Autoconf 2.61, there is a 
big long block starting:

# Compile and link our simple test program by passing a flag (argument
# 1 to this macro) to the Fortran compiler in order to get
# "verbose" output that we can then parse for the Fortran linker
# flags.

it then defines a:

ac_fc_v_output=`eval $ac_link 5>&1 2>&1 | grep -v 'Driving:'`

and proceeds to filter it heavily.  This code gets confused if you have 
a --with-stage1-libs='...' option in your compiler config line; in 
particular, if you have

--with-stage1-libs='/usr/lib/gcc/i686-redhat-linux/4.4.4/libstdc++.a -lm'

This code puts "-lm'" (with a single quote) into the list of libraries, 
which it of course can never find.

I have been patching around this in generated configure scripts by adding:

================
*** configure.orig      2012-09-28 14:12:48.000000000 -0500
--- configure   2012-09-28 14:12:50.000000000 -0500
***************
*** 3307,3312 ****
--- 3307,3315 ----
  echo "$ac_fc_v_output" >&5
  FCFLAGS=$ac_save_FFLAGS

+ # address@hidden -- clean out --with-stage1-libs bits...
+ ac_fc_v_output=`echo "$ac_fc_v_output" | sed -e 
"s/--with-stage1-libs='[^']*'//"`
+
  rm -f conftest*

  # On HP/UX there is a line like: "LPATH is: /foo:/bar:/baz" where

=============

but it would be nice to get this additional filter put into the actual 
autoconf code base.

It appears this text comes from the macro: _AC_PROG_FC_V_OUTPUT in 
fortran.m4


To reproduce:

1) build a gcc with gfortran configured with
    --with-stage1-libs='-lm -lm'
  (or other pair of libraries) (this is needed if you want to build
  --static ,for example)
2) try to configure something with Fortran with that gcc/gfortran.
   (for example http://lhapdf.hepforge.org/)

To fix:

Add the line filtering out /--with-stage1-libs='[^']*'/ from 
ac_fc_v_output to fortran.m4 above the "rm -rf conftest *" line around 
line 560.


Marc Mengel <address@hidden>