build(cmake): simplify def_cmd_target function

Instead of appending to a command output, append to an existing target
instead. The primary benefit is intermediary ...-cmd targets aren't
needed, we can instead append commands to the relevant target directly.

1 files changed, 12 insertions, 20 deletions

diff --git a/cmake/DefCmdTarget.cmake b/cmake/DefCmdTarget.cmake
index 1ee5cdd60e..48e90cf5c8 100644
--- a/cmake/DefCmdTarget.cmake
+++ b/cmake/DefCmdTarget.cmake
@@ -1,27 +1,19 @@
-# Defines a target named ${target} and a command with (symbolic) output
-# ${target}-cmd. If ${prg} is undefined the target prints "not found".
+# Defines a target named ${target}. If ${prg} is undefined the target prints
+# "not found".
 #
-# - Use add_custom_command(…APPEND) to build the command after this.
-# - Use add_custom_target(…DEPENDS) to run the command from a target.
+# - Use add_custom_command(TARGET <target_name> ...) to append a command to the
+# target.
 function(def_cmd_target target prg prg_name prg_fatal)
-  # Define a mostly-empty command, which can be appended-to.
-  add_custom_command(OUTPUT ${target}-cmd
-      WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
-      COMMAND ${CMAKE_COMMAND} -E echo "${target}"
-  )
-  # Symbolic (does not generate an artifact).
-  set_source_files_properties(${target}-cmd PROPERTIES SYMBOLIC "true")
+  add_custom_target(${target})
 
-  if(prg OR NOT prg_fatal)
-    add_custom_target(${target}
-      WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
-      DEPENDS ${target}-cmd)
-    if(NOT prg)
-      add_custom_command(OUTPUT ${target}-cmd APPEND
+  if(NOT prg)
+    if(prg_fatal)
+      add_custom_command(TARGET ${target}
+        COMMAND ${CMAKE_COMMAND} -E echo "${target}: ${prg_name} not found"
+        COMMAND false)
+    else()
+      add_custom_command(TARGET ${target}
         COMMAND ${CMAKE_COMMAND} -E echo "${target}: SKIP: ${prg_name} not found")
     endif()
-  else()
-    add_custom_target(${target} false
-      COMMENT "${target}: ${prg_name} not found")
   endif()
 endfunction()