diff --git a/browser/branding/aurora/moz.build b/browser/branding/aurora/moz.build
index 0faef59f9f64..3e2f88f1e364 100644
--- a/browser/branding/aurora/moz.build
+++ b/browser/branding/aurora/moz.build
@@ -6,3 +6,5 @@
 
 DIRS += ['content', 'locales']
 
+DIST_SUBDIR = 'browser'
+export('DIST_SUBDIR')
diff --git a/browser/branding/nightly/moz.build b/browser/branding/nightly/moz.build
index 8f320daeae90..3e2f88f1e364 100644
--- a/browser/branding/nightly/moz.build
+++ b/browser/branding/nightly/moz.build
@@ -5,3 +5,6 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 DIRS += ['content', 'locales']
+
+DIST_SUBDIR = 'browser'
+export('DIST_SUBDIR')
diff --git a/browser/branding/official/moz.build b/browser/branding/official/moz.build
index 0faef59f9f64..3e2f88f1e364 100644
--- a/browser/branding/official/moz.build
+++ b/browser/branding/official/moz.build
@@ -6,3 +6,5 @@
 
 DIRS += ['content', 'locales']
 
+DIST_SUBDIR = 'browser'
+export('DIST_SUBDIR')
diff --git a/browser/branding/unofficial/moz.build b/browser/branding/unofficial/moz.build
index 0faef59f9f64..3e2f88f1e364 100644
--- a/browser/branding/unofficial/moz.build
+++ b/browser/branding/unofficial/moz.build
@@ -6,3 +6,5 @@
 
 DIRS += ['content', 'locales']
 
+DIST_SUBDIR = 'browser'
+export('DIST_SUBDIR')
diff --git a/browser/defs.mk b/browser/defs.mk
index 3eb73eb502f8..fd88c6585e27 100644
--- a/browser/defs.mk
+++ b/browser/defs.mk
@@ -1,2 +1 @@
-DIST_SUBDIR=browser
 XPI_ROOT_APPID=$(MOZ_APP_ID)
diff --git a/browser/installer/Makefile.in b/browser/installer/Makefile.in
index a9986c2aff99..bd4fc845b152 100644
--- a/browser/installer/Makefile.in
+++ b/browser/installer/Makefile.in
@@ -3,6 +3,7 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 STANDALONE_MAKEFILE := 1
+DIST_SUBDIR := browser
 
 include $(topsrcdir)/config/rules.mk
 
diff --git a/browser/metro/base/Makefile.in b/browser/metro/base/Makefile.in
index 7a75e28d24d1..baebac1ccb8f 100644
--- a/browser/metro/base/Makefile.in
+++ b/browser/metro/base/Makefile.in
@@ -4,8 +4,6 @@
 
 include $(topsrcdir)/config/config.mk
 
-DIST_SUBDIR=metro
-
 DEFINES += -DAB_CD=$(MOZ_UI_LOCALE) \
            -DPACKAGE=browser \
            -DMOZ_APP_VERSION=$(MOZ_APP_VERSION) \
diff --git a/browser/metro/base/moz.build b/browser/metro/base/moz.build
index 3c1ae49fa55d..cad3b48d9a9e 100644
--- a/browser/metro/base/moz.build
+++ b/browser/metro/base/moz.build
@@ -6,3 +6,5 @@
 
 METRO_CHROME_MANIFESTS += ['tests/mochiperf/metro.ini', 'tests/mochitest/metro.ini']
 XPCSHELL_TESTS_MANIFESTS += ['tests/unit/xpcshell.ini']
+
+DIST_SUBDIR = 'metro'
diff --git a/browser/metro/defs.mk b/browser/metro/defs.mk
index 363987e8bd62..bd6e60829958 100644
--- a/browser/metro/defs.mk
+++ b/browser/metro/defs.mk
@@ -1,2 +1 @@
-DIST_SUBDIR=metro
 XPI_ROOT_APPID={99bceaaa-e3c6-48c1-b981-ef9b46b67d60}
diff --git a/browser/metro/moz.build b/browser/metro/moz.build
index 6ddbb5971077..a9000ff375aa 100644
--- a/browser/metro/moz.build
+++ b/browser/metro/moz.build
@@ -15,3 +15,5 @@ DIRS += [
 
 if CONFIG['OS_ARCH'] == 'WINNT':
     DIRS += ['shell']
+
+DIST_SUBDIR = 'metro'
diff --git a/browser/metro/shell/commandexecutehandler/Makefile.in b/browser/metro/shell/commandexecutehandler/Makefile.in
index 814d9b3f481b..7a040be9c963 100644
--- a/browser/metro/shell/commandexecutehandler/Makefile.in
+++ b/browser/metro/shell/commandexecutehandler/Makefile.in
@@ -6,9 +6,6 @@ NO_PROFILE_GUIDED_OPTIMIZE = 1
 
 include $(topsrcdir)/config/config.mk
 
-# We want this exe in dist/bin
-DIST_SUBDIR =
-
 DIST_PROGRAM = CommandExecuteHandler$(BIN_SUFFIX)
 
 # Don't link against mozglue.dll
diff --git a/browser/metro/shell/commandexecutehandler/moz.build b/browser/metro/shell/commandexecutehandler/moz.build
index 9def8c68341d..696705ed771a 100644
--- a/browser/metro/shell/commandexecutehandler/moz.build
+++ b/browser/metro/shell/commandexecutehandler/moz.build
@@ -10,3 +10,6 @@ CPP_SOURCES += [
     'CEHHelper.cpp',
     'CommandExecuteHandler.cpp',
 ]
+
+# We want this exe in dist/bin
+DIST_SUBDIR = ''
diff --git a/browser/metro/shell/linktool/Makefile.in b/browser/metro/shell/linktool/Makefile.in
index b2892028fbfc..1160f3eff214 100644
--- a/browser/metro/shell/linktool/Makefile.in
+++ b/browser/metro/shell/linktool/Makefile.in
@@ -6,8 +6,6 @@ NO_PROFILE_GUIDED_OPTIMIZE = 1
 
 include $(topsrcdir)/config/config.mk
 
-DIST_SUBDIR = metro/install
-
 OS_LIBS = \
 	kernel32.lib \
 	user32.lib \
diff --git a/browser/metro/shell/linktool/moz.build b/browser/metro/shell/linktool/moz.build
index 440a82cc419e..0ab8223b24fc 100644
--- a/browser/metro/shell/linktool/moz.build
+++ b/browser/metro/shell/linktool/moz.build
@@ -9,3 +9,5 @@ PROGRAM = 'linktool'
 CPP_SOURCES += [
     'linktool.cpp',
 ]
+
+DIST_SUBDIR = 'metro/install'
diff --git a/browser/metro/shell/testing/Makefile.in b/browser/metro/shell/testing/Makefile.in
index 50efa245fa58..bfbb75abafc7 100644
--- a/browser/metro/shell/testing/Makefile.in
+++ b/browser/metro/shell/testing/Makefile.in
@@ -13,9 +13,6 @@ NO_PROFILE_GUIDED_OPTIMIZE = 1
 
 include $(topsrcdir)/config/config.mk
 
-# We want this exe in dist/bin
-DIST_SUBDIR =
-
 OS_LIBS = \
 	kernel32.lib \
 	user32.lib \
diff --git a/browser/metro/shell/testing/moz.build b/browser/metro/shell/testing/moz.build
index b8e7f9e92a77..430330b95a8f 100644
--- a/browser/metro/shell/testing/moz.build
+++ b/browser/metro/shell/testing/moz.build
@@ -9,3 +9,6 @@ PROGRAM = 'metrotestharness'
 CPP_SOURCES += [
     'metrotestharness.cpp',
 ]
+
+# We want this exe in dist/bin
+DIST_SUBDIR = ''
diff --git a/browser/moz.build b/browser/moz.build
index c0c3fcf0154b..45b4fa1b11de 100644
--- a/browser/moz.build
+++ b/browser/moz.build
@@ -27,3 +27,5 @@ if CONFIG['MOZ_METRO']:
 if CONFIG['MAKENSISU']:
     DIRS += ['installer/windows']
 
+DIST_SUBDIR = 'browser'
+export('DIST_SUBDIR')
diff --git a/python/mozbuild/mozbuild/frontend/reader.py b/python/mozbuild/mozbuild/frontend/reader.py
index 5013324072a8..45b7f440d8c9 100644
--- a/python/mozbuild/mozbuild/frontend/reader.py
+++ b/python/mozbuild/mozbuild/frontend/reader.py
@@ -710,7 +710,7 @@ class BuildReader(object):
                                    'var': var}
                 if 'exports' in sandbox.metadata:
                     sandbox.recompute_exports()
-                    recurse_info[d]['exports'] = sandbox.metadata['exports']
+                    recurse_info[d]['exports'] = dict(sandbox.metadata['exports'])
 
         # We also have tiers whose members are directories.
         if 'TIERS' in sandbox:
diff --git a/webapprt/Makefile.in b/webapprt/Makefile.in
index 885e59ae8509..2453d0bbd833 100644
--- a/webapprt/Makefile.in
+++ b/webapprt/Makefile.in
@@ -5,9 +5,6 @@
 # Include config.mk explicitly so we can override FINAL_TARGET.
 include $(topsrcdir)/config/config.mk
 
-# Place webapprt resources in a separate app dir
-DIST_SUBDIR = webapprt
-
 PREF_JS_EXPORTS = $(srcdir)/prefs.js \
                   $(NULL)
 
diff --git a/webapprt/defs.mk b/webapprt/defs.mk
index 02d807a413e3..e3ed0d8cbf4d 100644
--- a/webapprt/defs.mk
+++ b/webapprt/defs.mk
@@ -1,2 +1 @@
-DIST_SUBDIR=webapprt
 XPI_ROOT_APPID=webapprt@mozilla.org
diff --git a/webapprt/moz.build b/webapprt/moz.build
index 001be545a469..0f29f8aca76c 100644
--- a/webapprt/moz.build
+++ b/webapprt/moz.build
@@ -32,3 +32,6 @@ EXTRA_JS_MODULES += [
 MOCHITEST_WEBAPPRT_CHROME_MANIFESTS += ['test/chrome/webapprt.ini']
 MOCHITEST_MANIFESTS += ['test/content/mochitest.ini']
 
+# Place webapprt resources in a separate app dir
+DIST_SUBDIR = 'webapprt'
+export('DIST_SUBDIR')