Core/Misc: Add valgrind support for jemalloc

Set CMake option VALGRIND to add valgrind support to jemalloc. Set CMake parameter VALGRIND_INCLUDE_DIR to the valgrind include directory.

cmake/showoptions.cmake

@@ -106,6 +106,13 @@ if ( NOJEM )
   message(" *** jemalloc linking has been disabled!")
   message(" *** Please note that this is for DEBUGGING WITH VALGRIND only!")
   message(" *** DO NOT DISABLE IT UNLESS YOU KNOW WHAT YOU'RE DOING!")
+elseif ( VALGRIND )
+  message("")
+  message(" *** VALGRIND - WARNING!")
+  message(" *** jemalloc will be configured to support Valgrind")
+  message(" *** Please specify the valgrind include directory in VALGRIND_INCLUDE_DIR option if you get build errors")
+  message(" *** Please note that this is for DEBUGGING WITH VALGRIND only!")
+  add_definitions(-DJEMALLOC_VALGRIND)
 endif()
 
 if ( HELGRIND )