--- nyan/CMakeLists.txt.orig	2018-07-12 20:09:17 UTC
+++ nyan/CMakeLists.txt
@@ -11,7 +11,7 @@ if (APPLE)
     endif ()
 endif ()
 
-find_package(FLEX 2.6 REQUIRED)
+find_package(FLEX 2.5 REQUIRED)
 
 set(nyanl_cpp "${CMAKE_CURRENT_BINARY_DIR}/flex.gen.cpp")
 set(nyanl_h "${CMAKE_CURRENT_BINARY_DIR}/flex.gen.h")
@@ -77,10 +77,15 @@ add_library(nyan SHARED
 add_library(nyan::nyan ALIAS nyan)
 
 if(UNIX)
-	target_link_libraries(nyan
-		${CMAKE_DL_LIBS}
-	)
-
+	if("${CMAKE_SYSTEM_NAME}" MATCHES "(Free|Net|Open)BSD")
+	  find_library(EXECINFO_LIBRARY execinfo)
+	  target_link_libraries(nyan ${CMAKE_DL_LIBS} ${EXECINFO_LIBRARY})
+        elseif("${CMAKE_SYSTEM_NAME}" MATCHES "DragonFly")
+	  find_library(EXECINFO_LIBRARY execinfo)
+	  target_link_libraries(nyan ${CMAKE_DL_LIBS} ${EXECINFO_LIBRARY})
+	else()
+	   target_link_libraries(nyan ${CMAKE_DL_LIBS})
+	endif()
 	if(NOT APPLE)
 		# for ld on macOS: "The default is to treat undefined symbols as errors."
 		set_target_properties(nyan PROPERTIES LINK_FLAGS "-Wl,--no-undefined")