Replace language_support module with builtin CheckLanguage

The workaround_9220 function was introduced a long time ago to
workaround a CMake issue with enable_language(OPTIONAL). Since then
CMake has clarified that the OPTIONAL keywords has not been
implemented[0].

A CheckLanguage module is now provided with CMake to check if a language
can be enabled. Use that instead.

[0] https://cmake.org/cmake/help/v3.18/command/enable_language.html

1 files changed, 0 insertions, 67 deletions

diff --git a/cmake/language_support.cmake b/cmake/language_support.cmake
deleted file mode 100644
index 591fca523..000000000
--- a/cmake/language_support.cmake
+++ /dev/null
@@ -1,67 +0,0 @@
-# cmake/modules/language_support.cmake
-#
-# Temporary additional general language support is contained within this
-# file.  
-
-# This additional function definition is needed to provide a workaround for
-# CMake bug 9220.
-
-# On debian testing (cmake 2.6.2), I get return code zero when calling 
-# cmake the first time, but cmake crashes when running a second time
-# as follows:
-#
-#  -- The Fortran compiler identification is unknown
-#  CMake Error at /usr/share/cmake-2.6/Modules/CMakeFortranInformation.cmake:7 (GET_FILENAME_COMPONENT):
-#    get_filename_component called with incorrect number of arguments
-#  Call Stack (most recent call first):
-#    CMakeLists.txt:3 (enable_language)
-#
-# My workaround is to invoke cmake twice.  If both return codes are zero, 
-# it is safe to invoke enable_language(Fortran OPTIONAL)
-
-function(workaround_9220 language language_works)
-  #message("DEBUG: language = ${language}")
-  set(text
-    "project(test NONE)
-    cmake_minimum_required(VERSION 2.8.11)
-    set (CMAKE_Fortran_FLAGS \"${CMAKE_Fortran_FLAGS}\")
-    set (CMAKE_EXE_LINKER_FLAGS \"${CMAKE_EXE_LINKER_FLAGS}\")
-    enable_language(${language})
-  ")
-  file(REMOVE_RECURSE ${CMAKE_BINARY_DIR}/language_tests/${language})
-  file(MAKE_DIRECTORY ${CMAKE_BINARY_DIR}/language_tests/${language})
-  file(WRITE ${CMAKE_BINARY_DIR}/language_tests/${language}/CMakeLists.txt
-    ${text})
-  execute_process(
-    COMMAND ${CMAKE_COMMAND} . -G "${CMAKE_GENERATOR}" -DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM}
-    WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/language_tests/${language}
-    RESULT_VARIABLE return_code
-    OUTPUT_QUIET
-    ERROR_QUIET
-    )
-
-  if(return_code EQUAL 0)
-    # Second run
-    execute_process (
-      COMMAND ${CMAKE_COMMAND} . -G "${CMAKE_GENERATOR}" -DCMAKE_MAKE_PROGRAM=${CMAKE_MAKE_PROGRAM}
-      WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/language_tests/${language}
-      RESULT_VARIABLE return_code
-      OUTPUT_QUIET
-      ERROR_QUIET
-      )
-    if(return_code EQUAL 0)
-      set(${language_works} ON PARENT_SCOPE)
-    else()
-      set(${language_works} OFF PARENT_SCOPE)
-    endif()
-  else()
-    set(${language_works} OFF PARENT_SCOPE)
-  endif()
-endfunction()
-
-# Temporary tests of the above function.
-#workaround_9220(CXX CXX_language_works)
-#message("CXX_language_works = ${CXX_language_works}")
-#workaround_9220(CXXp CXXp_language_works)
-#message("CXXp_language_works = ${CXXp_language_works}")
-