[bugfix][CMake][Release] Use named arguments in DuneSymlinkOrCopy

Passing multiple files to dune_symlink_to_source_files() was broken.
While at it, I switched the given macros to be functions and have
named arguments. Using positional arguments will result in a warning.

cmake/modules/DuneSymlinkOrCopy.cmake

@@ -27,16 +27,16 @@
 # in the source tree. This file will be copied
 # to the build tree.
 #
-#   dune_symlink_to_source_tree()
+#   dune_symlink_to_source_tree([NAME name])
 #
-# add a symlink called src_dir to all directories in the build tree.
+# add a symlink called NAME to all directories in the build tree (defaults to src_dir).
 # That symlink points to the corresponding directory in the source tree.
 # Call the macro from the toplevel CMakeLists.txt file of your project.
 # You can also call it from some other directory, creating only symlinks
 # in that directory and all directories below. A warning is issued on
 # Windows systems.
 #
-#  dune_symlink_to_source_files(files)
+#   dune_symlink_to_source_files(FILES files)
 #
 # add symlinks to the build tree, which point to files in the source tree.
 # Foreach file given in "files", a symlink of that name is created in the
@@ -63,7 +63,14 @@ macro(dune_add_copy_dependency target file_name)
     add_dependencies(${target} "${target}_copy_${file_name}")
 endmacro(dune_add_copy_dependency)
 
-macro(dune_symlink_to_source_tree)
+function(dune_symlink_to_source_tree)
+  # parse arguments
+  include(CMakeParseArguments)
+  cmake_parse_arguments(ARG "" "NAME" "" ${ARGN})
+  if(NOT ARG_NAME)
+    set(ARG_NAME "src_dir")
+  endif()
+
   # check for Windows to issue a warning
   if(${CMAKE_SYSTEM_NAME} STREQUAL "Windows")
     if(NOT DEFINED DUNE_WINDOWS_SYMLINK_WARNING)
@@ -78,15 +85,22 @@ macro(dune_symlink_to_source_tree)
     foreach(f ${files})
       get_filename_component(dir ${f} DIRECTORY)
       if(NOT "${CMAKE_SOURCE_DIR}/${dir}" MATCHES "${CMAKE_BINARY_DIR}/*")
-        execute_process(COMMAND ${CMAKE_COMMAND} "-E" "create_symlink" "${CMAKE_SOURCE_DIR}/${dir}" "${CMAKE_BINARY_DIR}/${dir}/src_dir")
+        execute_process(COMMAND ${CMAKE_COMMAND} "-E" "create_symlink" "${CMAKE_SOURCE_DIR}/${dir}" "${CMAKE_BINARY_DIR}/${dir}/${ARG_NAME}")
       endif(NOT "${CMAKE_SOURCE_DIR}/${dir}" MATCHES "${CMAKE_BINARY_DIR}/*")
     endforeach()
   endif()
-endmacro(dune_symlink_to_source_tree)
+endfunction(dune_symlink_to_source_tree)
+
+function(dune_symlink_to_source_files)
+  # parse arguments
+  include(CMakeParseArguments)
+  cmake_parse_arguments(ARG "" "" "FILES" ${ARGN})
+  if(ARG_UNPARSED_ARGUMENTS)
+    message(WARNING "You are using dune_symlink_to_source_files without named arguments (or have typos in your named arguments)!")
+  endif()
 
-macro(dune_symlink_to_source_files files)
   # create symlinks for all given files
-  foreach(f ${files})
+  foreach(f ${ARG_FILES})
     # check for Windows to issue a warning
     if(${CMAKE_SYSTEM_NAME} STREQUAL "Windows")
       if(NOT DEFINED DUNE_WINDOWS_SYMLINK_WARNING)
@@ -99,4 +113,4 @@ macro(dune_symlink_to_source_files files)
       execute_process(COMMAND ${CMAKE_COMMAND} "-E" "create_symlink" "${CMAKE_CURRENT_SOURCE_DIR}/${f}" "${CMAKE_CURRENT_BINARY_DIR}/${f}")
     endif()
   endforeach()
-endmacro(dune_symlink_to_source_files files)
+endfunction(dune_symlink_to_source_files)