now also builds correctly on OS X

extdep/cryptopp.cmake

@@ -1,5 +1,6 @@
 # CryptoPP does not have good cross-platform support, there exist several different other projects to make it work ... 
 
+# TODO the OS X build throws a lot of warnings, but compiles fine
 if(APPLE)
     ExternalProject_Add(cryptopp
          URL https://downloads.sourceforge.net/project/cryptopp/cryptopp/5.6.2/cryptopp562.zip

libweb3jsonrpc/CMakeLists.txt

@@ -25,6 +25,7 @@ if(MINIUPNPC_LS)
 	target_link_libraries(${EXECUTABLE} ${MINIUPNPC_LS})
 endif()
 target_link_libraries(${EXECUTABLE} ${LEVELDB_LS})
+target_link_libraries(${EXECUTABLE} ${JSONCPP_LIBRARIES})
 target_link_libraries(${EXECUTABLE} ${JSON_RPC_CPP_LIBRARIES})
 if(READLINE_LS)
 target_link_libraries(${EXECUTABLE} ${READLINE_LS})