Fix compiling on MacOSX Systems

Setting those options made OSX quite upset for some reason, so disable them when on Macs. I haven't been able to find any issues with this, so hopefully it doesn't subtly break anything.

Additionally, this will add the default MacPorts library directory to the LD Path, which fixes linking against Log4CPP.

CMakeLists.txt

@@ -2,7 +2,12 @@ cmake_minimum_required(VERSION 2.8.0)
 project(mumlib)
 
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
-add_definitions(-DOPT_TLS_GNUTLS -D_POSIX_C_SOURCE=200112L)
+
+if (NOT APPLE)
+  add_definitions(-DOPT_TLS_GNUTLS -D_POSIX_C_SOURCE=200112L)
+else()
+  LINK_DIRECTORIES(/opt/local/lib) # Include the default MacPorts library directory
+endif()
 
 INCLUDE(FindPkgConfig)
 find_package(PkgConfig REQUIRED)