fix official gmake on windows builds; use check for null value instead of

gmake's origin function, so local makefiles can unset OFFICIAL vars for
versioning purposes. r= aki, cls

config/mkdepend/Makefile.in

@@ -26,8 +26,11 @@ VPATH		= @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
-MODULE		= mkdepend
-PROGRAM		= mkdepend$(BIN_SUFFIX)
+# undefine (as best we can, thanks gmake!) so we don't need build_number
+MOZILLA_OFFICIAL =
+BUILD_OFFICIAL   =
+MODULE		 = mkdepend
+PROGRAM		 = mkdepend$(BIN_SUFFIX)
 ifdef GNU_CC
 MODULE_OPTIMIZE_FLAGS = -O3
 else

config/version.mk

@@ -51,7 +51,7 @@ ifndef RESFILE
 RCFILE=./module.rc
 RESFILE=./module.res
 _RC_STRING = -QUIET 1 -DEPTH $(DEPTH) -TOPSRCDIR $(topsrcdir) -BITS $(MOZ_BITS) -OBJDIR . -SRCDIR $(srcdir)
-ifneq ($(origin BUILD_OFFICIAL)_$(origin MOZILLA_OFFICIAL),undefined_undefined)
+ifneq ($(BUILD_OFFICIAL)_$(MOZILLA_OFFICIAL),_)
 _RC_STRING += -OFFICIAL 1
 endif
 ifdef MOZ_DEBUG