cmake: enable Fortran

[lfoldy]

opensuse tumbleweed:

cmake -DBLAS_LIBRARIES=openblas ../lapack-3.12.0

-- Looking for Fortran dgemm
CMake Error at /usr/share/cmake/Modules/CheckFortranFunctionExists.cmake:69 (try_compile):
  Unknown extension ".f" for file

    /tmp/build/CMakeFiles/CMakeScratch/TryCompile-6Nl0AU/testFortranCompiler.f

  try_compile() works only for enabled languages.  Currently these are:

    C CXX

  See project() command to enable other languages.
Call Stack (most recent call first):
  CMakeLists.txt:228 (CHECK_FORTRAN_FUNCTION_EXISTS)

cmake version is 3.27.7

[weslleyspereira]

We missed a enable_language(Fortran) in the CMakelists.txt. #948 should fix it. Please let us know if it doesn't.