Installing root 6.x from source on Mac OS 10.11 fails with a fortran error

[kwells]

When installing root 6.08 or 6.10 on my Mac using cmake, I get the following error:

The Fortran compiler "/usr/local/bin/gfortran" is not able to compile a
  simple test program.

  It fails with the following output:

   Change Dir: /Users/kwells/Development/physics/chroma_env/src/root-build/CMakeFiles/CMakeTmp

  Run Build Command:"/usr/bin/make" "cmTC_84fce/fast"

  /Applications/Xcode.app/Contents/Developer/usr/bin/make -f
  CMakeFiles/cmTC_84fce.dir/build.make CMakeFiles/cmTC_84fce.dir/build

  Building Fortran object CMakeFiles/cmTC_84fce.dir/testFortranCompiler.f.o

  /usr/local/bin/gfortran -c
  /Users/kwells/Development/physics/chroma_env/src/root-build/CMakeFiles/CMakeTmp/testFortranCompiler.f
  -o CMakeFiles/cmTC_84fce.dir/testFortranCompiler.f.o

  FATAL:/opt/local/bin/../libexec/as/x86_64/as: I don't understand 'm' flag!

  make[1]: *** [CMakeFiles/cmTC_84fce.dir/testFortranCompiler.f.o] Error 1

  make: *** [cmTC_84fce/fast] Error 2

  CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
  cmake/modules/CheckCompiler.cmake:11 (enable_language)
  CMakeLists.txt:35 (include)

I have tried various methods for installing gcc/gfortran with no success.

Thanks in advance,
Kevin

[Danilo]

Hi,

it looks like you have some brew(?) installation of gnu binutils (for example as).
You can have a look at https://root.cern.ch/build-prerequisites#macosx but a first step could consist in removing all of the aforementioned packages (as, gcc/gfortran installed, as you say, “with various methods”) and install the xcode command line utilities to then retry the CMake configuration.

xcode-select --install

Cheers,
Danilo

[kwells]

Thank you for the response. That has fixed the issue. I was thrown off because I not longer have a gfortran executable. But I guess the make process is smart enough to deal with that!

[Danilo]

Hi,

great you solved that! Yes,in general it is…

Cheers,
D