From NetBSD:
Force proper LDFLAGS for MODULE, as cmake doesn't set rpath for these
Index: 3d-viewer/3d_cache/sg/CMakeLists.txt
--- 3d-viewer/3d_cache/sg/CMakeLists.txt.orig
+++ 3d-viewer/3d_cache/sg/CMakeLists.txt
@@ -43,6 +43,9 @@ if( APPLE )
     )
 endif()
 
+set_property(TARGET kicad_3dsg APPEND_STRING
+       PROPERTY LINK_FLAGS " $ENV{LDFLAGS}")
+
 find_file( S3DSG_VERSION_FILE sg_version.h
         PATHS ${CMAKE_SOURCE_DIR}/include/plugins/3dapi NO_DEFAULT_PATH NO_CMAKE_FIND_ROOT_PATH)
 
