correctly handle the situation that the build folder may have multiple libs downloaded

cmake/Modules/LAMMPSUtils.cmake

@@ -24,6 +24,24 @@ function(validate_option name values)
     endif()
 endfunction(validate_option)
 
+# helper function for getting the most recently modified file or folder from a glob pattern
+function(get_newest_file path variable)
+  file(GLOB _dirs ${path})
+  set(_besttime 2000-01-01T00:00:00)
+  set(_bestfile "<unknown>")
+  foreach(_dir ${_dirs})
+    file(TIMESTAMP ${_dir} _newtime)
+    if(_newtime IS_NEWER_THAN _besttime)
+      set(_bestfile ${_dir})
+      set(_besttime ${_newtime})
+    endif()
+  endforeach()
+  if(_bestfile STREQUAL "<unknown>")
+    message(FATAL_ERROR "Could not find valid path at: ${path}")
+  endif()
+  set(${variable} ${_bestfile} PARENT_SCOPE)
+endfunction()
+
 function(get_lammps_version version_header variable)
     file(STRINGS ${version_header} line REGEX LAMMPS_VERSION)
     set(MONTHS x Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec)

cmake/Modules/Packages/ML-PACE.cmake

@@ -13,8 +13,8 @@ execute_process(
   COMMAND ${CMAKE_COMMAND} -E tar xzf libpace.tar.gz
   WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
 )
+get_newest_file(${CMAKE_BINARY_DIR}/lammps-user-pace-* lib-pace)
 
-file(GLOB lib-pace ${CMAKE_BINARY_DIR}/lammps-user-pace-*)
 # enforce building libyaml-cpp as static library and turn off optional features
 set(YAML_BUILD_SHARED_LIBS OFF)
 set(YAML_CPP_BUILD_CONTRIB OFF)