Build fails with ldc2

[Russel Winder]

Running CMake without options uses gdc. Running CMake with -DCMAKE_D_COMPILER=dmd works fine. However running with -DCMAKE_D_COMPILER=ldc2 leads to:

-- Configuring done
You have changed variables that require your cache to be deleted.
Configure will be re-run and you may have to reset some variables.
The following variables have changed:
CMAKE_D_COMPILER= ldc2

-- The D compiler identification is LDC
-- Check for working D compiler: /usr/bin/ldc2
-- Check for working D compiler: /usr/bin/ldc2 -- broken
-- To force a specific D compiler set the DC environment variable
--     ie - export DC="/usr/bin/dmd"
CMake Error at cmake-d/CMakeTestDCompiler.cmake:45 (message):
  The D compiler "/usr/bin/ldc2" is not able to compile a simple test
  program.

  It fails with the following output:

   Change Dir: /home/users/russel/BuildArea/HelloWorld_D_CMake/CMakeFiles/CMakeTmp

  

  Run Build Command:"/usr/bin/ninja" "cmTC_89a73"

  [1/2] Building D object CMakeFiles/cmTC_89a73.dir/testDCompiler

  [2/2] Linking D executable cmTC_89a73

  FAILED: cmTC_89a73

  : && /usr/bin/ldc2 CMakeFiles/cmTC_89a73.dir/testDCompiler -ofcmTC_89a73 &&
  :

  Error: module testDCompiler is in file
  'CMakeFiles/cmTC_89a73.dir/testDCompiler.d' which cannot be read

  import path[0] = /usr/include/d

  import path[1] = /usr/lib/ldc/x86_64-linux-gnu/include/d/ldc

  import path[2] = /usr/lib/ldc/x86_64-linux-gnu/include/d

  ninja: build stopped: subcommand failed.

  

  

  CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
  CMakeLists.txt:5 (project)


-- Configuring incomplete, errors occurred!

[Dragos Carp]

CMake does not allow to change the compiler after you selected one. Simply remove the directory or the cache and start again, or specify another build directory.
See: https://cmake.org/Wiki/CMake_FAQ#I_change_CMAKE_C_COMPILER_in_the_GUI_but_it_changes_back_on_the_next_configure_step._Why.3F

BTW also try to select the compiler using the DC shell environment variable. Example: DC=ldc2 cmake -D...