WIP:

-  no auto-download of user-pace src yet
-  lib/pace/*.cpp,*.h are provided explicitly yet.
- implement CMake integration in USER-PACE.cmake and in CMakeLists.txt

cmake/Modules/Packages/USER-PACE.cmake

@@ -0,0 +1,14 @@
+set(PACE_EVALUATOR_PATH ${LAMMPS_LIB_SOURCE_DIR}/pace)
+message("CMakeLists.txt DEBUG: PACE_EVALUATOR_PATH=${PACE_EVALUATOR_PATH}")
+set(PACE_EVALUATOR_SRC_PATH ${PACE_EVALUATOR_PATH})
+
+FILE(GLOB PACE_EVALUATOR_SOURCE_FILES ${PACE_EVALUATOR_SRC_PATH}/*.cpp)
+set(PACE_EVALUATOR_INCLUDE_DIR ${PACE_EVALUATOR_SRC_PATH})
+
+
+##### aceevaluator #####
+add_library(aceevaluator ${PACE_EVALUATOR_SOURCE_FILES})
+target_include_directories(aceevaluator PUBLIC ${PACE_EVALUATOR_INCLUDE_DIR})
+target_compile_options(aceevaluator PRIVATE -O2)
+set_target_properties(aceevaluator PROPERTIES OUTPUT_NAME lammps_pace${LAMMPS_MACHINE})
+target_link_libraries(lammps PRIVATE aceevaluator)