Fix MKL finding with Intel 2021 and newer (#640)

.github/workflows/fortran-build.yml

@@ -195,7 +195,7 @@ jobs:
         printenv >> $GITHUB_ENV
 
     - name: Configure meson build
-      run: meson setup ${{ env.BUILD_DIR }} --prefix=/ -Dfortran_args=-qopenmp
+      run: meson setup ${{ env.BUILD_DIR }} --prefix=/
 
     - name: Build project
       run: ninja -C ${{ env.BUILD_DIR }}

meson.build

@@ -45,7 +45,10 @@ endif
 # We rely on the existence of Python since meson will need a Python interpreter to run,
 # this way we have a cross-platform way to obtain relevant data for our build.
 pymod = import('python')
-python = pymod.find_installation('python3')
+python = pymod.find_installation('python3', required: false)
+if not python.found()
+  python = find_program('python3', 'python')
+endif
 
 # build a configuration data containing all the important data to propagate
 # it to the automatically generated files

meson/meson.build

@@ -108,29 +108,29 @@ if la_backend == 'mkl' or la_backend == 'mkl-static'
   endif
 
   if get_option('default_library') == 'dynamic'
-    mkl_rt_dep = fc.find_library('mkl_rt', required: true)
+    mkl_rt_dep = cc.find_library('mkl_rt', required: true)
     lib_deps += libmkl_exe
   else
     if fc.get_id() == 'gcc'
-      libmkl_exe = [fc.find_library('mkl_gf_lp64')]
+      libmkl_exe = [cc.find_library('mkl_gf_lp64')]
       if get_option('openmp')
-        libmkl_exe += fc.find_library('mkl_gnu_thread')
+        libmkl_exe += cc.find_library('mkl_gnu_thread')
       endif
     elif fc.get_id() == 'intel' or fc.get_id() == 'intel-cl'
-      libmkl_exe = [fc.find_library('mkl_intel_lp64')]
+      libmkl_exe = [cc.find_library('mkl_intel_lp64')]
       if get_option('openmp')
-        libmkl_exe += fc.find_library('mkl_intel_thread')
+        libmkl_exe += cc.find_library('mkl_intel_thread')
       endif
     elif fc.get_id() == 'pgi' or fc.get_id() == 'nvidia_hpc'
-      libmkl_exe = [fc.find_library('mkl_intel_lp64')]
+      libmkl_exe = [cc.find_library('mkl_intel_lp64')]
       if get_option('openmp')
-        libmkl_exe += fc.find_library('mkl_pgi_thread')
+        libmkl_exe += cc.find_library('mkl_pgi_thread')
       endif
     endif
     if not get_option('openmp')
-      libmkl_exe += fc.find_library('mkl_sequential')
+      libmkl_exe += cc.find_library('mkl_sequential')
     endif
-    libmkl_exe += fc.find_library('mkl_core')
+    libmkl_exe += cc.find_library('mkl_core')
     lib_deps += libmkl_exe
   endif