Make WebSockets demos compile on Linux

examples/C/src/lib/WebSocketCmake.txt

@@ -1,3 +1,5 @@
 find_package(libwebsockets REQUIRED) # Finds the libwebsockets library
 
-target_link_libraries( ${LF_MAIN_TARGET} websockets ) # Links the websockets library
+# Note that the PUBLIC keyword is needed otherwise CMake will issue an error
+# saying that you must use either all-keywords or all-plain, and the keywords are previously used. 
+target_link_libraries( ${LF_MAIN_TARGET} PUBLIC websockets ) # Links the websockets library