--- a/build/moz.configure/init.configure
+++ b/build/moz.configure/init.configure
@@ -255,16 +255,17 @@ def wanted_mozconfig_variables(help):
          'DSYMUTIL',
          'EXTERNAL_SOURCE_DIR',
          'GENISOIMAGE',
          'L10NBASEDIR',
          'MOZILLABUILD',
          'MOZ_ARTIFACT_BUILDS',
          'MOZ_BUILD_APP',
          'MOZ_CALLGRIND',
+         'MOZ_DMD',
          'MOZ_FMP4',
          'MOZ_INSTRUMENT_EVENT_LOOP',
          'MOZ_INSTRUMENTS',
          'MOZ_JPROF',
          'MOZ_USE_SYSTRACE',
          'MOZTTDIR',
          'PERL',
          'RPMBUILD',

--- a/build/moz.configure/old.configure
+++ b/build/moz.configure/old.configure
@@ -186,17 +186,16 @@ def old_configure_options(*options):
     '--enable-crashreporter',
     '--enable-ctypes',
     '--enable-dbm',
     '--enable-dbus',
     '--enable-debug',
     '--enable-debug-js-modules',
     '--enable-debug-symbols',
     '--enable-directshow',
-    '--enable-dmd',
     '--enable-dtrace',
     '--enable-dump-painting',
     '--enable-elf-hack',
     '--enable-extensions',
     '--enable-faststripe',
     '--enable-feeds',
     '--enable-gamepad',
     '--enable-gc-trace',

--- a/old-configure.in
+++ b/old-configure.in
@@ -1250,34 +1250,26 @@ if test "$MOZ_PROFILING" -a -z "$STRIP_F
         ;;
     esac
 fi
 
 dnl ========================================================
 dnl = Enable DMD
 dnl ========================================================
 
-MOZ_ARG_ENABLE_BOOL(dmd,
-[  --enable-dmd            Enable DMD; also enables jemalloc, replace-malloc and profiling],
-    MOZ_DMD=1,
-    MOZ_DMD= )
-
 if test "$MOZ_DMD"; then
-    AC_DEFINE(MOZ_DMD)
-
     if test "${CPU_ARCH}" = "arm"; then
         CFLAGS="$CFLAGS -funwind-tables"
         CXXFLAGS="$CXXFLAGS -funwind-tables"
     fi
 
     MOZ_MEMORY=1                        # DMD enables jemalloc
     MOZ_REPLACE_MALLOC=1                # DMD enables replace-malloc
     MOZ_PROFILING=1                     # DMD enables profiling
 fi
-AC_SUBST(MOZ_DMD)
 
 dnl ========================================================
 dnl Profiling
 dnl ========================================================
 if test -n "$MOZ_PROFILING"; then
     AC_DEFINE(MOZ_PROFILING)
 fi
 

--- a/toolkit/moz.configure
+++ b/toolkit/moz.configure
@@ -42,16 +42,28 @@ def sps_profiler(target):
 
 @depends(sps_profiler)
 def sps_profiler_define(value):
     if value:
         set_config('MOZ_ENABLE_PROFILER_SPS', '1')
         set_define('MOZ_ENABLE_PROFILER_SPS', '1')
 
 
+option('--enable-dmd', env='MOZ_DMD',
+       help='Enable Dark Matter Detector (heap profiler). '
+            'Also enables jemalloc, replace-malloc and profiling')
+
+@depends('--enable-dmd')
+def dmd(value):
+    if value:
+        set_config('MOZ_DMD', '1')
+        set_define('MOZ_DMD', '1')
+        add_old_configure_assignment('MOZ_DMD', '1')
+
+
 # Javascript engine
 # ==============================================================
 include('../js/moz.configure')
 
 
 # L10N
 # ==============================================================
 option('--with-l10n-base', nargs=1, env='L10NBASEDIR',