diff --git a/CMakeLists.txt b/CMakeLists.txt
index c8da424..269486b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -274,6 +274,10 @@ if(WIN32)
 endif(WIN32)
 # end readline stuff
 
+if( NOT CPP_STANDARD )
+  set( CPP_STANDARD, "-std=c++11" )
+endif()
+
 IF(WIN32)
   target_compile_definitions(fc PUBLIC WIN32 NOMINMAX _WIN32_WINNT=0x0501 _CRT_SECURE_NO_WARNINGS
     _SCL_SERCURE_NO_WARNINGS
@@ -295,12 +299,12 @@ ELSE()
   SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c99 -Wall")
 
   IF(APPLE)
-    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -stdlib=libc++ -Wall")
+    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CPP_STANDARD} -stdlib=libc++ -Wall")
   ELSE()
     if( NOT "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" )
-      target_compile_options(fc PUBLIC -std=c++11 -Wall -fnon-call-exceptions)
+      target_compile_options(fc PUBLIC ${CPP_STANDARD} -Wall -fnon-call-exceptions)
     endif()
-    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -fnon-call-exceptions")
+    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CPP_STANDARD} -Wall -fnon-call-exceptions")
   ENDIF()
 ENDIF()
 
@@ -319,6 +323,7 @@ if( ZLIB_FOUND )
   add_definitions( -DHAS_ZLIB )
 else()
   MESSAGE( STATUS "zlib not found" )
+  set( ZLIB_LIBRARIES "" )
 endif( ZLIB_FOUND )
 
 find_package( BZip2 )
@@ -327,6 +332,7 @@ if( BZIP2_FOUND )
    add_definitions( -DHAS_BZIP2 )
 else()
    MESSAGE( STATUS "bzip2 not found" )
+   set( BZIP2_LIBRARIES "" )
 endif( BZIP2_FOUND )
 
 # This will become unnecessary once we update to websocketpp which fixes upstream issue #395