Attempt to fix potential conflicts with system headers on Windows

Don't copy the clang headers, which can conflict with the system headers, like for example "future" which can now be put back in the pch headers list

build/unix/makepchinput.py

@@ -138,6 +138,7 @@ def getSTLIncludes():
                      "atomic",
                      "thread",
                      "mutex",
+                     "future",
                      "condition_variable",
                      "ciso646",
                      "ccomplex",
@@ -145,9 +146,6 @@ def getSTLIncludes():
                      "cstdalign",
                      "cstdbool")
 
-   if sys.platform != 'win32':
-      stlHeadersList += ("future",)
-
    allHeadersPartContent = "// STL headers\n"
 
    for header in stlHeadersList:

core/clingutils/CMakeLists.txt

@@ -119,7 +119,14 @@ foreach(file wchar.h bits/stat.h bits/time.h)
 endforeach()
 
 set(stamp_file ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/LLVMRES.stamp)
-add_custom_command(OUTPUT ${stamp_file}
+if(MSVC)
+  add_custom_command(OUTPUT ${stamp_file}
+        COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_BINARY_DIR}/etc/cling/lib/clang/${LLVM_VERSION}/include
+        COMMAND ${CMAKE_COMMAND} -E touch ${stamp_file}
+        ${copy_commands}
+        DEPENDS ${files_to_copy})
+else()
+  add_custom_command(OUTPUT ${stamp_file}
         COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_BINARY_DIR}/etc/cling/lib/clang/${CLANG_RESOURCE_DIR_VERSION}/include
         COMMAND ${CMAKE_COMMAND} -E copy_directory
         ${CLANG_RESOURCE_DIR}
@@ -137,5 +144,6 @@ add_custom_command(OUTPUT ${stamp_file}
         COMMAND ${CMAKE_COMMAND} -E touch ${stamp_file}
         DEPENDS ${files_to_copy}
         COMMENT "Copying LLVM resource and header files")
+endif()
 add_custom_target(LLVMRES DEPENDS ${stamp_file} CLING)