FindMPI: Use compiler implicit link dirs for matching language (#14870)

Update the logic added by commit 2f9ad7c6 (Fix FindMPI for the intel
compiler on linux, 2012-03-20) to use the implicit link directories for
the current ${lang} instead of hard-coding C or CXX which may not be
enabled.  This is necessary for Fortran-only projects.

Modules/FindMPI.cmake

@@ -378,19 +378,14 @@ function (interrogate_mpi_compiler lang try_libs)
         # Extract the set of libraries to link against from the link command
         # line
         string(REGEX MATCHALL "(^| )-l([^\" ]+|\"[^\"]+\")" MPI_LIBNAMES "${MPI_LINK_CMDLINE}")
+
         # add the compiler implicit directories because some compilers
         # such as the intel compiler have libraries that show up
         # in the showme list that can only be found in the implicit
-        # link directories of the compiler. Do this for C++ and C
-        # compilers if the implicit link directories are defined.
-        if (DEFINED CMAKE_CXX_IMPLICIT_LINK_DIRECTORIES)
-          set(MPI_LINK_PATH
-            "${MPI_LINK_PATH};${CMAKE_CXX_IMPLICIT_LINK_DIRECTORIES}")
-        endif ()
-
-        if (DEFINED CMAKE_C_IMPLICIT_LINK_DIRECTORIES)
+        # link directories of the compiler.
+        if (DEFINED CMAKE_${lang}_IMPLICIT_LINK_DIRECTORIES)
           set(MPI_LINK_PATH
-            "${MPI_LINK_PATH};${CMAKE_C_IMPLICIT_LINK_DIRECTORIES}")
+            "${MPI_LINK_PATH};${CMAKE_${lang}_IMPLICIT_LINK_DIRECTORIES}")
         endif ()
 
         # Determine full path names for all of the libraries that one needs