--- a/client.mk
+++ b/client.mk
@@ -124,16 +124,17 @@ export FOUND_MOZCONFIG
 MOZCONFIG_OUT_LINES := $(subst $(CR), ,$(subst $(NULL) $(NULL),||,$(MOZCONFIG_CONTENT)))
 # Filter-out comments from those lines.
 START_COMMENT = \#
 MOZCONFIG_OUT_FILTERED := $(filter-out $(START_COMMENT)%,$(MOZCONFIG_OUT_LINES))
 
 ifdef AUTOCLOBBER
 export AUTOCLOBBER=1
 endif
+export MOZ_PGO
 
 ifdef MOZ_PARALLEL_BUILD
   MOZ_MAKE_FLAGS := $(filter-out -j%,$(MOZ_MAKE_FLAGS))
   MOZ_MAKE_FLAGS += -j$(MOZ_PARALLEL_BUILD)
 endif
 
 # Automatically add -jN to make flags if not defined. N defaults to number of cores.
 ifeq (,$(findstring -j,$(MOZ_MAKE_FLAGS)))

--- a/configure.in
+++ b/configure.in
@@ -6792,16 +6792,17 @@ fi
 fi # COMPILE_ENVIRONMENT
 
 AC_SUBST(MOZ_OPTIMIZE)
 AC_SUBST(MOZ_FRAMEPTR_FLAGS)
 AC_SUBST(MOZ_OPTIMIZE_FLAGS)
 AC_SUBST(MOZ_OPTIMIZE_LDFLAGS)
 AC_SUBST(MOZ_ALLOW_HEAP_EXECUTE_FLAGS)
 AC_SUBST(MOZ_OPTIMIZE_SIZE_TWEAK)
+AC_SUBST(MOZ_PGO)
 AC_SUBST(MOZ_PGO_OPTIMIZE_FLAGS)
 
 dnl ========================================================
 dnl = Enable any treating of compile warnings as errors
 dnl ========================================================
 MOZ_ARG_ENABLE_BOOL(warnings-as-errors,
 [  --enable-warnings-as-errors
                           Enable treating of warnings as errors],

--- a/testing/gtest/Makefile.in
+++ b/testing/gtest/Makefile.in
@@ -2,29 +2,34 @@
 # 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/.
 
 # Avoid recursive make to avoid having to add files to the gtest/ subdirectory
 # (which is third-party code), and to make the build faster.
 
 include $(topsrcdir)/config/rules.mk
 
+# Bug 1028035: Linking xul-gtest.dll takes too long, so we disable GTest on
+# Windows PGO builds.
+ifeq (1WINNT,$(MOZ_PGO)$(OS_ARCH))
+SKIP_GTEST_DURING_MAKE_CHECK ?= 1
+endif
+
 ifeq (browser,$(MOZ_BUILD_APP))
-# Disable because of metro linking error bug 883339:
-# LNK1181: cannot open input file 'runtimeobject.lib'
-# And non metro linking error bug 886656:
-# LNK1112: module machine type 'x64' conflicts with target machine type 'X86'
-ifneq ($(OS_ARCH),WINNT)
 ifdef COMPILE_ENVIRONMENT
 gtest::
 	$(MAKE) -C $(DEPTH)/toolkit/library gtestxul
 ifeq (cocoa,$(MOZ_WIDGET_TOOLKIT))
 	$(MAKE) -C $(DEPTH)/browser/app repackage
 endif
+ifneq (1,$(SKIP_GTEST_DURING_MAKE_CHECK))
 check::
 	$(MAKE) -C $(DEPTH)/toolkit/library gtestxul
 ifeq (cocoa,$(MOZ_WIDGET_TOOLKIT))
 	$(MAKE) -C $(DEPTH)/browser/app repackage
 endif
 	$(PYTHON) $(topsrcdir)/testing/gtest/rungtests.py --xre-path=$(DIST)/bin --symbols-path=$(DIST)/crashreporter-symbols $(DIST)/bin/$(MOZ_APP_NAME)$(BIN_SUFFIX)
+else
+check::
+	echo GTest skipped during make check
 endif
 endif
 endif