--- a/browser/config/mozconfigs/linux32/nightly
+++ b/browser/config/mozconfigs/linux32/nightly
@@ -1,12 +1,13 @@
 . "$topsrcdir/browser/config/mozconfigs/linux32/common-opt"
 
 ac_add_options --enable-profiling
 ac_add_options --enable-verify-mar
+ac_add_options --enable-dmd
 
 # This will overwrite the default of stripping everything and keep the symbol table.
 # This is useful for profiling and debugging and only increases the package size
 # by 2 MBs.
 STRIP_FLAGS="--strip-debug"
 
 ac_add_options --with-branding=browser/branding/nightly
 

--- a/browser/config/mozconfigs/linux64/nightly
+++ b/browser/config/mozconfigs/linux64/nightly
@@ -1,12 +1,13 @@
 . "$topsrcdir/browser/config/mozconfigs/linux64/common-opt"
 
 ac_add_options --enable-profiling
 ac_add_options --enable-verify-mar
+ac_add_options --enable-dmd
 
 # This will overwrite the default of stripping everything and keep the symbol table.
 # This is useful for profiling and debugging and only increases the package size
 # by 2 MBs.
 STRIP_FLAGS="--strip-debug"
 
 ac_add_options --with-branding=browser/branding/nightly
 

--- a/browser/config/mozconfigs/macosx64/nightly
+++ b/browser/config/mozconfigs/macosx64/nightly
@@ -1,14 +1,15 @@
 . "$topsrcdir/browser/config/mozconfigs/macosx64/common-opt"
 
 ac_add_options --disable-install-strip
 ac_add_options --enable-verify-mar
 ac_add_options --enable-profiling
 ac_add_options --enable-instruments
+ac_add_options --enable-dmd
 
 # Cross-compiled builds fail when dtrace is enabled
 if test `uname -s` != Linux; then
   ac_add_options --enable-dtrace
 fi
 
 if test "${MOZ_UPDATE_CHANNEL}" = "nightly"; then
 ac_add_options --with-macbundlename-prefix=Firefox

--- a/browser/config/mozconfigs/win32/nightly
+++ b/browser/config/mozconfigs/win32/nightly
@@ -1,9 +1,10 @@
 . "$topsrcdir/build/mozconfig.win-common"
 . "$topsrcdir/browser/config/mozconfigs/win32/common-opt"
 
 ac_add_options --enable-profiling
 ac_add_options --enable-verify-mar
+ac_add_options --enable-dmd
 
 ac_add_options --with-branding=browser/branding/nightly
 
 . "$topsrcdir/build/mozconfig.common.override"

--- a/browser/config/mozconfigs/win64/common-opt
+++ b/browser/config/mozconfigs/win64/common-opt
@@ -1,16 +1,17 @@
 # This file is sourced by the nightly, beta, and release mozconfigs.
 
 . "$topsrcdir/build/mozconfig.stylo"
 
 . "$topsrcdir/browser/config/mozconfigs/common"
 
 ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
 ac_add_options --enable-jemalloc
+
 if [ -f /c/builds/gapi.data ]; then
   _gapi_keyfile=c:/builds/gapi.data
 else
   _gapi_keyfile=e:/builds/gapi.data
 fi
 ac_add_options --with-google-api-keyfile=${_gapi_keyfile}
 
 ac_add_options --with-mozilla-api-keyfile=c:/builds/mozilla-desktop-geoloc-api.key

--- a/browser/config/mozconfigs/win64/nightly
+++ b/browser/config/mozconfigs/win64/nightly
@@ -1,10 +1,11 @@
 . "$topsrcdir/build/mozconfig.win-common"
 . "$topsrcdir/browser/config/mozconfigs/win64/common-win64"
 . "$topsrcdir/browser/config/mozconfigs/win64/common-opt"
 
 ac_add_options --enable-profiling
 ac_add_options --enable-verify-mar
+ac_add_options --enable-dmd
 
 ac_add_options --with-branding=browser/branding/nightly
 
 . "$topsrcdir/build/mozconfig.common.override"