Fortran runtime library detection fails with modern Cray compilers

[Steve Vormwald]

Hello,

The _AC_FC_LIBRARY_LDFLAGS macro in lib/autoconf/fortran.m4 is incompatible 
with modern Cray compiler drivers.  Unlike most other compilers, the Cray C/C++ 
compiler drivers require no additional flags to properly link with Cray Fortran 
object files.  Also unlike most other compilers, the Cray compiler drivers 
default to creating a statically linked executable, with a few runtime 
libraries linked whole-archive.  When autoconf explicitly passes these link 
options to the driver, the compilation fails due to duplicate symbols from the 
runtime library being included multiple times.  The attached patch filters out 
the library that is causing problems with CCE 8.0.x-8.2.x.  A better solution 
would be to automatically filter out libraries that the C/C++ compiler drivers 
add, as this particular library (part of the gperftools project at 
http://code.google.com/p/gperftools/) is not specific to Cray.

Steven Vormwald

fortran.m4.patch
Description: fortran.m4.patch