Revert "Remove UNIX path"

This reverts commit c873c6a.

slimt/CMakeLists.txt

@@ -108,6 +108,14 @@ foreach(SLIMT_LIB IN LISTS SLIMT_LIBRARIES)
   target_compile_definitions(${SLIMT_LIB} PRIVATE ${SLIMT_COMPILE_DEFINITIONS})
 endforeach()
 
+if(UNIX)
+  install(FILES ${SLIMT_PUBLIC_HEADERS}
+          DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/slimt)
+  install(FILES ${SLIMT_GENERATED_HEADERS}
+          DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/slimt/)
+  install(TARGETS ${SLIMT_LIBRARIES} DESTINATION ${CMAKE_INSTALL_LIBDIR})
+endif(UNIX)
+
 # The following is partial code for enabling `find_package(slimt ...)` Not
 # working at the moment, due to the inablility to export sentencepiece
 # (accounting for it as an installed target).