CMake 3.16 has included pch support, use this instead of cotire.

CMakeLists.txt

@@ -99,9 +99,11 @@ include(ExternalProject)
 
 include(cmake/compile_defs.cmake)
 include(cmake/release.cmake)
-include(cmake/cotire.cmake)
-#hide the cotire settings
-hide_cotire()
+if (${CMAKE_VERSION} VERSION_LESS "3.16")
+  include(cmake/cotire.cmake)
+  #hide the cotire settings
+  hide_cotire()
+endif()
 
 fix_compiler_flags()
 detect_compiler()

cmake/compile_defs.cmake

@@ -183,9 +183,23 @@ function(source_group_by_folder target)
 endfunction()
 
 function (enable_pch target)
+  # optional argument REUSE or REUSE_COTIRE
+  # cmake starting with 3.16:
+  # REUSE and REUSE_COTIRE will use clib pch
+  # older cmake with cotire:
+  # REUSE_COTIRE will create new pch with clib stdafx
+  set(argn "${ARGN}")
   if (NOT NO_PCH)
     set(_pch_name "${CMAKE_CURRENT_SOURCE_DIR}/StdAfx.h")
-    if (EXISTS ${_pch_name})
+    if (${CMAKE_VERSION} VERSION_LESS "3.16")
+      if (NOT EXISTS ${_pch_name})
+        if ("REUSE_COTIRE" STREQUAL "${argn}")
+          set(_pch_name "${CMAKE_CURRENT_SOURCE_DIR}/../clib/StdAfx.h")
+        else()
+          return()
+        endif()
+      endif()
+
       set_target_properties(${target} PROPERTIES COTIRE_CXX_PREFIX_HEADER_INIT ${_pch_name})
       set_target_properties(${target} PROPERTIES COTIRE_ADD_UNITY_BUILD OFF)
       cotire(${target})
@@ -195,6 +209,12 @@ function (enable_pch target)
           add_dependencies(${target}_pch boost)
         endif()
       endif()
+    else()
+      if ("${argn}" MATCHES "REUSE.*")
+        target_precompile_headers(${target} REUSE_FROM clib)
+      else()
+        target_precompile_headers(${target} PUBLIC ${_pch_name})
+      endif()
     endif()
   endif()
 endfunction()

pol-core/ecompile/CMakeLists.txt

@@ -23,3 +23,4 @@ endif()
 dist(${ex_name} scripts)
 
 use_tidy(${ex_name})
+enable_pch(${ex_name} REUSE)

pol-core/ecompile/CMakeSources.cmake

@@ -2,7 +2,6 @@ set (ecompile_sources  # sorted !
   CMakeSources.cmake 
   ECompileMain.cpp
   ECompileMain.h
-  StdAfx.h
   ecompile.ico
   ecompile.rc
   resource.h

pol-core/poltool/CMakeLists.txt

@@ -18,3 +18,4 @@ target_link_libraries(${ex_name} PUBLIC
 dist(${ex_name} .)
 
 use_tidy(${ex_name})
+enable_pch(${ex_name} REUSE)

pol-core/poltool/CMakeSources.cmake

@@ -2,5 +2,4 @@ set (poltool_sources  # sorted !
   CMakeSources.cmake 
   PolToolMain.cpp
   PolToolMain.h
-  StdAfx.h
 )

pol-core/runecl/CMakeLists.txt

@@ -9,7 +9,7 @@ add_executable(${ex_name}
 
 set_compile_flags(${ex_name} 1)
 warning_suppression(${ex_name})
-enable_pch(${ex_name})
+enable_pch(${ex_name} REUSE_COTIRE)
 
 target_link_libraries(${ex_name} PUBLIC
   bscript

pol-core/runecl/CMakeSources.cmake

@@ -15,5 +15,4 @@ set (runecl_sources  # sorted !
   CMakeSources.cmake 
   RunEclMain.cpp
   RunEclMain.h
-  StdAfx.h
 )

pol-core/uoconvert/CMakeLists.txt

@@ -23,3 +23,4 @@ endif()
 dist(${ex_name} .)
 
 use_tidy(${ex_name})
+enable_pch(${ex_name} REUSE)

pol-core/uoconvert/CMakeSources.cmake

@@ -1,6 +1,5 @@
 set (uoconvert_sources  # sorted !
   CMakeSources.cmake 
-  StdAfx.h
   UoConvertMain.cpp
   UoConvertMain.h
   resource.h

pol-core/uotool/CMakeLists.txt

@@ -9,7 +9,7 @@ add_executable(${ex_name}
 
 set_compile_flags(${ex_name} 1)
 warning_suppression(${ex_name})
-enable_pch(${ex_name})
+enable_pch(${ex_name} REUSE_COTIRE)
 
 target_link_libraries(${ex_name} PUBLIC
   clib

pol-core/uotool/CMakeSources.cmake

@@ -2,7 +2,6 @@ set (uotool_sources  # sorted !
   ../pol/globals/multidefs.cpp
   ../pol/multi/multidef.cpp
   CMakeSources.cmake 
-  StdAfx.h
   UoToolMain.cpp
   UoToolMain.h
 )