stop building ODBC driver under linux if gcc 4.8.0 is chosen as the compiler

src/connector/odbc/CMakeLists.txt

@@ -17,11 +17,15 @@ IF (TD_LINUX_64)
       if(NOT FLEX_FOUND)
         message(FATAL_ERROR "you need to install flex first")
       else ()
-        SET(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -Wconversion")
-        SET(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -Wconversion")
-        ADD_SUBDIRECTORY(src)
-        ADD_SUBDIRECTORY(tools)
-        ADD_SUBDIRECTORY(tests)
+        if (CMAKE_C_COMPILER_ID STREQUAL "GNU" AND CMAKE_C_COMPILER_VERSION VERSION_LESS 5.0.0)
+          message(WARNING "gcc 4.8.0 will complain too much about flex-generated code, we just bypass building ODBC driver in such case")
+        else ()
+          SET(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -Wconversion")
+          SET(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} -Wconversion")
+          ADD_SUBDIRECTORY(src)
+          ADD_SUBDIRECTORY(tools)
+          ADD_SUBDIRECTORY(tests)
+        endif ()
       endif()
     endif()
   ELSE ()