Description of problem:

The compat-libgfortran-41-4.1.2-44 library providing libgfortran.so.1 does not link against libquadmath.so.0 (the DSO providing the <func>q named symbols):

$ nm -D /lib64/libgfortran.so.1 | grep sqrtq
                 U csqrtq
                 U sqrtq
$ objdump -p /lib64/libgfortran.so.1 | grep NEEDED
  NEEDED libm.so.6
  NEEDED libc.so.6

$ ldd /lib64/libgfortran.so.1
        linux-vdso.so.1 => (0x00007ffc5b1cf000)
        libm.so.6 => /lib64/libm.so.6 (0x00007fdd39c9e000)
        libc.so.6 => /lib64/libc.so.6 (0x00007fdd398d1000)
        /lib64/ld-linux-x86-64.so.2 (0x00007fdd3a289000)

therefore legacy applications (built on Red Hat 5) fail to load. The example to reproduce the issue is quite specific to our business, please excuse that.

I haven't been able to find a better way to show the problem but that is only because of my total lack of knowledge of Fortran and how it works.

We have some legacy applications embedded in a stack of software that we would like to run on Red Hat 7.

Version-Release number of selected component (if applicable):

Latest: 4.1.2-44

How reproducible:

Always

Steps to Reproduce:

Prerequisites:
* gcc 4.1.2 - vanilla build on Red Hat 6 or system gcc on Red Hat 5
* python 2.6.4 - vanilla build from source code with above gcc 4.1.2
* atlas 3.8.4 vanilla build compiled with above gcc 4.1.2
* Numpy 1.7.1 source code

Steps:
* Build numpy 1.7.1 (with atlas support) built with gcc 4.1.2 on Redhat 5 or 6
$ python2.6 setup.py build

* Try to import lapack_lite.so on the build machine. It works.
$ cd <build-dir>/build/lib.linux-x86_64-2.6
$ python2.6 -c 'import numpy.linalg.lapack_lite'
$ (no import error - success)

* Importing it on Red Hat 7
$ cd <build-dir>/build/lib.linux-x86_64-2.6
$ env LD_LIBRARY_PATH=$PYTHON26DIR/lib $PYTHON26DIR/bin/python -c 'import numpy.linalg.lapack_lite'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ImportError: /lib64/libgfortran.so.1: undefined symbol: sqrtq

Actual results:


Expected results:


Additional info:

To fix the issue, I've rebuilt compat-libgfortran-41 with "-lquadmath" explicitly added to LDFLAGS. The resulting libgfortran.so.1 had the correct linkage and no python import error occurred.

Alternatively, LD_PRELOAD'ing libquadmath.so.0 also works.