Create .la files at the end of the cmake run

We might not have all the necessary information, e.g. all targets might
not exist yet, until we're done going through all CMakeLists.

CMakeLists.txt

@@ -348,3 +348,5 @@ configure_file("${CMAKE_SOURCE_DIR}/cmake/cmake_uninstall.cmake.in"
   "cmake_uninstall.cmake" IMMEDIATE @ONLY)
 
 add_custom_target(uninstall COMMAND ${CMAKE_COMMAND} -P cmake_uninstall.cmake)
+
+libtool_generate_control_files()

cmake/Modules/CMakeMacroLibtoolFile.cmake

@@ -1,4 +1,20 @@
-macro(libtool_create_control_file _target)
+# FIXME: Since we cannot require CMake 3.17, we cannot used deferred
+#        functions, and hence we have to do something similar manually
+
+set_property(GLOBAL PROPERTY LIBTOOL_TARGETS "")
+
+function(libtool_create_control_file target)
+  set_property(GLOBAL APPEND PROPERTY LIBTOOL_TARGETS ${target})
+endfunction()
+
+function(libtool_generate_control_files)
+  get_property(LIBTOOL_TARGETS GLOBAL PROPERTY LIBTOOL_TARGETS)
+  foreach(target ${LIBTOOL_TARGETS})
+    libtool_generate_control_file(${target})
+  endforeach()
+endfunction()
+
+function(libtool_generate_control_file _target)
   get_target_property(_target_type ${_target} TYPE)
 
   message("-- Creating static libtool control file for target ${_target}")
@@ -141,9 +157,11 @@ macro(libtool_create_control_file _target)
     endif()
   endforeach()
 
+  get_target_property(_binary_dir ${_target} BINARY_DIR)
+
   # Write the libtool control file for the static library
   set(_lname ${CMAKE_STATIC_LIBRARY_PREFIX}${_target})
-  set(_laname ${CMAKE_CURRENT_BINARY_DIR}/${_lname}.la)
+  set(_laname ${_binary_dir}/${_lname}.la)
 
   file(WRITE ${_laname} "# ${_lname}.la - a libtool library file\n# Generated by ltmain.sh (GNU libtool) 2.2.6b\n")
   file(APPEND ${_laname} "dlname=''\n\n")
@@ -162,15 +180,18 @@ macro(libtool_create_control_file _target)
   file(APPEND ${_laname} "libdir='/usr/lib'\n\n")
 
   # Make sure the timestamp is updated to trigger other make invocations
-  add_custom_command(TARGET ${_target} POST_BUILD COMMAND
-    "${CMAKE_COMMAND}" -E touch "${_laname}")
-
+  add_custom_command(OUTPUT "${_laname}" DEPENDS ${_target}
+    COMMENT "Updating timestamp on ${_lname}.la"
+    COMMAND "${CMAKE_COMMAND}" -E touch "${_laname}")
 
   # Add custom command to symlink the static library so that autotools finds
   # the library in .libs.  These are executed after the specified target build.
-  add_custom_command(TARGET ${_target} POST_BUILD COMMAND 
-    "${CMAKE_COMMAND}" -E make_directory "${CMAKE_CURRENT_BINARY_DIR}/.libs")
-  add_custom_command(TARGET ${_target} POST_BUILD COMMAND
-    "${CMAKE_COMMAND}" -E create_symlink ../${_lname}${CMAKE_STATIC_LIBRARY_SUFFIX} "${CMAKE_CURRENT_BINARY_DIR}/.libs/${_lname}${CMAKE_STATIC_LIBRARY_SUFFIX}")
-
-endmacro()
+  set(_libname ${_binary_dir}/.libs/${_lname}${CMAKE_STATIC_LIBRARY_SUFFIX})
+  add_custom_command(OUTPUT "${_libname}" DEPENDS ${_target}
+    COMMENT "Creating symlink .libs/${_lname}${CMAKE_STATIC_LIBRARY_SUFFIX}"
+    COMMAND "${CMAKE_COMMAND}" -E make_directory "${_binary_dir}/.libs"
+    COMMAND "${CMAKE_COMMAND}" -E create_symlink ../${_lname}${CMAKE_STATIC_LIBRARY_SUFFIX} "${_libname}")
+
+  add_custom_target(${_target}.la ALL
+    DEPENDS "${_laname}" "${_libname}")
+endfunction()