Bug 1241416 - Create a tier for things happening before export. r=gps

While it would be possible to move those things in the export tier, it
is still interesting to have reporting for them separately, especially
considering I expect things to gradually move from the other tiers to
this new one.

While not entirely obvious, the recurse_pre-export target doesn't imply
actual recursion as long as the RecursiveMake backend doesn't emit
traversal information for it, so nothing will actually happen on this
target, but the interesting part is that it runs, per the generic
config/recurse.mk rules for tiers, between BUILDSTATUS TIER_START and
BUILDSTATUS TIER_FINISH, so that all its dependencies are accounted
as being part of the pre-export tier.

Makefile.in

@@ -158,20 +158,20 @@ endif
 ifdef MOZ_PROFILE_USE
 ifndef NO_PROFILE_GUIDED_OPTIMIZE
 ifneq ($(OS_ARCH)_$(GNU_CC), WINNT_)
-export:: install-manifests
+recurse_pre-export:: install-manifests
 binaries::
 	@$(MAKE) install-manifests NO_REMOVE=1 install_manifests=dist/include
 endif
 endif
 else # !MOZ_PROFILE_USE (normal build)
-export:: install-manifests
+recurse_pre-export:: install-manifests
 binaries::
 	@$(MAKE) install-manifests NO_REMOVE=1 install_manifests=dist/include
 endif
 
 # For historical reasons that are unknown, $(DIST)/sdk is always blown away
 # with no regard for PGO passes. This decision could probably be revisited.
-export:: install-dist/sdk
+recurse_pre-export:: install-dist/sdk
 
 ifndef JS_STANDALONE
 ifdef ENABLE_TESTS

config/baseconfig.mk

@@ -45,7 +45,7 @@ endif # WINNT
 ifndef INCLUDED_AUTOCONF_MK
 default::
 else
-TIERS := export $(if $(COMPILE_ENVIRONMENT),compile )misc libs tools
+TIERS := pre-export export $(if $(COMPILE_ENVIRONMENT),compile )misc libs tools
 endif
 
 # These defines are used to support the twin-topsrcdir model for comm-central.