Bug 1099430, part 一: Define MOZILLA_DIR early in the base makefiles, r=glandium.

This change allows us to use use MOZILLA_DIR even for changes in config.mk. The
corollary is that comm-central needs to define MOZILLA_DIR before calling into
baseconfig.mk, which it already does.

The change to the test Makefile is needed since it decides to skip including
config.mk, and hence baseconfig.mk, where it would need to grab the MOZILLA_DIR
declaration.

config/baseconfig.mk

@@ -131,3 +131,10 @@ $(foreach var,$(_MOZBUILD_EXTERNAL_VARIABLES) $(_DEPRECATED_VARIABLES),$(eval $(
 
 TIERS := export $(if $(COMPILE_ENVIRONMENT),compile )misc libs tools
 endif
+
+# These defines are used to support the twin-topsrcdir model for comm-central.
+ifdef MOZILLA_SRCDIR
+  MOZILLA_DIR = $(MOZILLA_SRCDIR)
+else
+  MOZILLA_DIR = $(topsrcdir)
+endif

config/rules.mk

@@ -20,10 +20,6 @@ INCLUDED_RULES_MK = 1
 # overwritten after including config.mk.
 _eval_for_side_effects := $(CHECK_MOZBUILD_VARIABLES)
 
-ifndef MOZILLA_DIR
-MOZILLA_DIR = $(topsrcdir)
-endif
-
 ifndef INCLUDED_CONFIG_MK
 include $(topsrcdir)/config/config.mk
 endif

config/tests/makefiles/autodeps/testor.tmpl

@@ -43,6 +43,7 @@ MKDIR ?= mkdir -p
 TOUCH ?= touch
 
 INCLUDED_CONFIG_MK = 1
+MOZILLA_DIR := $(topsrcdir)
 include $(topsrcdir)/config/rules.mk
 
 ##-------------------##