added missing pthread lib

CMakeLists.txt

@@ -106,7 +106,7 @@ if(WIN32)
 	target_link_libraries(libhl ws2_32 user32)
 	target_link_libraries(hl user32)
 else()
-    target_link_libraries(libhl m dl)
+    target_link_libraries(libhl m dl pthread)
 endif()
 
 #####################