From NetBSD:
Force proper LDFLAGS for MODULE, as cmake doesn't set rpath for these
Index: cvpcb/CMakeLists.txt
--- cvpcb/CMakeLists.txt.orig
+++ cvpcb/CMakeLists.txt
@@ -79,7 +79,7 @@ target_link_libraries( cvpcb_kiface
     )
 
 # -lrt must follow Boost on Linux platforms
-target_link_libraries( cvpcb_kiface $<$<BOOL:${UNIX_NOT_APPLE}>:rt> )
+#target_link_libraries( cvpcb_kiface $<$<BOOL:${UNIX_NOT_APPLE}>:rt> )
 
 set_source_files_properties( cvpcb.cpp PROPERTIES
     # The KIFACE is in cvpcb.cpp, export it:
@@ -89,6 +89,9 @@ set_source_files_properties( cvpcb.cpp PROPERTIES
 target_link_options( cvpcb_kiface PRIVATE
     $<$<BOOL:${KICAD_MAKE_LINK_MAPS}>:-Wl,--cref,-Map=_cvpcb.kiface.map>
     )
+
+set_property(TARGET cvpcb_kiface APPEND_STRING
+   PROPERTY LINK_FLAGS " $ENV{LDFLAGS}")
 
 # these 2 binaries are a matched set, keep them together:
 if( APPLE )
