Bug 1142403 - Enable jemalloc debug on debug builds. r=njn

configure.in

@@ -9050,6 +9050,9 @@ esac
 
 if test -z "$MOZ_NATIVE_JEMALLOC" -a "$MOZ_MEMORY" && test -n "$MOZ_JEMALLOC3" -o -n "$MOZ_REPLACE_MALLOC"; then
   ac_configure_args="--build=$build --host=$target --enable-stats --with-jemalloc-prefix=je_ --disable-valgrind"
+  if test -n "$MOZ_DEBUG"; then
+    ac_configure_args="$ac_configure_args --enable-debug"
+  fi
   # We're using memalign for _aligned_malloc in memory/build/mozmemory_wrap.c
   # on Windows, so just export memalign on all platforms.
   ac_configure_args="$ac_configure_args ac_cv_func_memalign=yes"