diff --git a/memory/Makefile.in b/memory/Makefile.in
index 5a403e80191c6..8f8ae705dd6e7 100644
--- a/memory/Makefile.in
+++ b/memory/Makefile.in
@@ -9,18 +9,4 @@ VPATH           = @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
-DIRS += mozjemalloc
-
-ifneq (,$(MOZ_JEMALLOC3)$(MOZ_REPLACE_MALLOC))
-ifndef MOZ_NATIVE_JEMALLOC
-DIRS += jemalloc
-endif
-endif
-
-DIRS += build
-
-ifeq ($(MOZ_REPLACE_MALLOC_LINKAGE),dummy library)
-DIRS += replace/dummy
-endif
-
 include $(topsrcdir)/config/rules.mk
diff --git a/memory/build/moz.build b/memory/build/moz.build
new file mode 100644
index 0000000000000..58ce5e273390f
--- /dev/null
+++ b/memory/build/moz.build
@@ -0,0 +1,5 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
diff --git a/memory/jemalloc/moz.build b/memory/jemalloc/moz.build
new file mode 100644
index 0000000000000..58ce5e273390f
--- /dev/null
+++ b/memory/jemalloc/moz.build
@@ -0,0 +1,5 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
diff --git a/memory/moz.build b/memory/moz.build
new file mode 100644
index 0000000000000..f980cb2027437
--- /dev/null
+++ b/memory/moz.build
@@ -0,0 +1,16 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+DIRS += ['mozjemalloc']
+
+if CONFIG['MOZ_JEMALLOC3'] or CONFIG['MOZ_REPLACE_MALLOC']:
+    if not CONFIG['MOZ_NATIVE_JEMALLOC']:
+        DIRS += ['jemalloc']
+
+DIRS += ['build']
+
+if CONFIG['MOZ_REPLACE_MALLOC_LINKAGE'] == 'dummy library':
+    DIRS += ['replace/dummy']
+
diff --git a/memory/mozalloc/moz.build b/memory/mozalloc/moz.build
new file mode 100644
index 0000000000000..58ce5e273390f
--- /dev/null
+++ b/memory/mozalloc/moz.build
@@ -0,0 +1,5 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
diff --git a/memory/mozjemalloc/moz.build b/memory/mozjemalloc/moz.build
new file mode 100644
index 0000000000000..58ce5e273390f
--- /dev/null
+++ b/memory/mozjemalloc/moz.build
@@ -0,0 +1,5 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
diff --git a/memory/replace/Makefile.in b/memory/replace/Makefile.in
index 9f92e18bca1b1..8f8ae705dd6e7 100644
--- a/memory/replace/Makefile.in
+++ b/memory/replace/Makefile.in
@@ -9,9 +9,4 @@ VPATH           = @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
-# Build jemalloc3 as a replace-malloc lib when building with mozjemalloc
-ifndef MOZ_JEMALLOC
-DIRS += jemalloc
-endif
-
 include $(topsrcdir)/config/rules.mk
diff --git a/memory/replace/dmd/moz.build b/memory/replace/dmd/moz.build
new file mode 100644
index 0000000000000..58ce5e273390f
--- /dev/null
+++ b/memory/replace/dmd/moz.build
@@ -0,0 +1,5 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
diff --git a/memory/replace/dummy/moz.build b/memory/replace/dummy/moz.build
new file mode 100644
index 0000000000000..58ce5e273390f
--- /dev/null
+++ b/memory/replace/dummy/moz.build
@@ -0,0 +1,5 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
diff --git a/memory/replace/jemalloc/moz.build b/memory/replace/jemalloc/moz.build
new file mode 100644
index 0000000000000..58ce5e273390f
--- /dev/null
+++ b/memory/replace/jemalloc/moz.build
@@ -0,0 +1,5 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
diff --git a/memory/replace/moz.build b/memory/replace/moz.build
new file mode 100644
index 0000000000000..cabbb25cf2552
--- /dev/null
+++ b/memory/replace/moz.build
@@ -0,0 +1,8 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+# Build jemalloc3 as a replace-malloc lib when building with mozjemalloc
+if not CONFIG['MOZ_JEMALLOC']:
+    DIRS += ['jemalloc']
diff --git a/mfbt/Makefile.in b/mfbt/Makefile.in
index 63f638035141e..781f00f032476 100644
--- a/mfbt/Makefile.in
+++ b/mfbt/Makefile.in
@@ -14,10 +14,6 @@ LIBRARY_NAME = mfbt
 FORCE_STATIC_LIB = 1
 STL_FLAGS =
 
-TEST_DIRS = \
-  tests \
-  $(NULL)
-
 # exported_headers.mk defines the headers exported by mfbt.  It is included by
 # mfbt itself and by the JS engine, which, when built standalone, must do the
 # work to install mfbt's exported headers itself.
diff --git a/mfbt/moz.build b/mfbt/moz.build
new file mode 100644
index 0000000000000..d0193307adbaf
--- /dev/null
+++ b/mfbt/moz.build
@@ -0,0 +1,6 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+TEST_DIRS += ['tests']
diff --git a/mfbt/tests/moz.build b/mfbt/tests/moz.build
new file mode 100644
index 0000000000000..58ce5e273390f
--- /dev/null
+++ b/mfbt/tests/moz.build
@@ -0,0 +1,5 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
diff --git a/mozglue/Makefile.in b/mozglue/Makefile.in
index ceb5cb3a528f9..c349a53c0f8f9 100644
--- a/mozglue/Makefile.in
+++ b/mozglue/Makefile.in
@@ -8,19 +8,4 @@ srcdir		= @srcdir@
 VPATH		= @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
-
-DIRS =
-
-ifdef MOZ_LINKER
-DIRS += linker
-endif
-
-ifeq (android,$(MOZ_WIDGET_TOOLKIT))
-DIRS += android
-endif
-
-DIRS += build
-
-TEST_DIRS = tests
-
 include $(topsrcdir)/config/rules.mk
diff --git a/mozglue/android/moz.build b/mozglue/android/moz.build
new file mode 100644
index 0000000000000..58ce5e273390f
--- /dev/null
+++ b/mozglue/android/moz.build
@@ -0,0 +1,5 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
diff --git a/mozglue/build/moz.build b/mozglue/build/moz.build
new file mode 100644
index 0000000000000..58ce5e273390f
--- /dev/null
+++ b/mozglue/build/moz.build
@@ -0,0 +1,5 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
diff --git a/mozglue/linker/moz.build b/mozglue/linker/moz.build
new file mode 100644
index 0000000000000..58ce5e273390f
--- /dev/null
+++ b/mozglue/linker/moz.build
@@ -0,0 +1,5 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
diff --git a/mozglue/moz.build b/mozglue/moz.build
new file mode 100644
index 0000000000000..920a99cf0bfdb
--- /dev/null
+++ b/mozglue/moz.build
@@ -0,0 +1,14 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+if CONFIG['MOZ_LINKER']:
+    DIRS += ['linker']
+
+if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'android':
+    DIRS += ['android']
+
+DIRS += ['build']
+
+TEST_DIRS += ['tests']
diff --git a/mozglue/tests/moz.build b/mozglue/tests/moz.build
new file mode 100644
index 0000000000000..58ce5e273390f
--- /dev/null
+++ b/mozglue/tests/moz.build
@@ -0,0 +1,5 @@
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+