Do not override the MacPorts install_name defaults.
--- cmake/macros.cmake.orig	2018-03-27 07:17:46.000000000 -0500
+++ cmake/macros.cmake	2018-03-27 07:37:39.000000000 -0500
@@ -70,10 +70,6 @@
         RUNTIME DESTINATION ${LASZIP_BIN_INSTALL_DIR}
         LIBRARY DESTINATION ${LASZIP_LIB_INSTALL_DIR}
         ARCHIVE DESTINATION ${LASZIP_LIB_INSTALL_DIR})
-    if (APPLE)
-        set_target_properties(${_name} PROPERTIES INSTALL_NAME_DIR
-            "@executable_path/../lib")
-    endif()
 endmacro(LASZIP_ADD_LIBRARY)
 
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