recover pull by branch and pull by date functionality back.

also recover all the error handling utility code so we can make sure
that environment variables are set right before executing.

client.mak

@@ -32,14 +32,34 @@ NGLAYOUT_PLUGINS = 1
 # Command macro defines
 #
 
+#//------------------------------------------------------------------------
+#// Figure out how to do the pull.
+#//------------------------------------------------------------------------
+!if "$(MOZ_BRANCH)" != ""
+CVS_BRANCH=-r $(MOZ_BRANCH)
+HAVE_BRANCH=1
+!else
+HAVE_BRANCH=0
+!endif
+
+!if "$(MOZ_DATE)" != ""
+CVS_BRANCH=-D "$(MOZ_DATE)"
+HAVE_DATE=1
+!else
+HAVE_DATE=0
+!endif
+
+!if $(HAVE_DATE) && $(HAVE_BRANCH)
+ERR_MESSAGE=$(ERR_MESSAGE)^
+Cannot specify both MOZ_BRANCH and MOZ_DATE
+!endif
+
 # let's be explicit about CVSROOT... some windows cvs clients
 # are too stupid to correctly work without the -d option 
-!if defined(MOZ_DATE)
-CVSCO = cvs -q co -P -D "$(MOZ_DATE)"
-!elseif defined(CVSROOT)
-CVSCO = cvs -d $(CVSROOT) -q co -P
+!if defined(CVSROOT)
+CVSCO = cvs -d $(CVSROOT) -q co $(CVS_BRANCH) -P
 !else
-CVSCO = cvs -q co -P
+CVSCO = cvs -q co $(CVS_BRANCH) -P
 !endif
 
 CVSCO_TAG = cvs -q co -P
@@ -110,3 +130,75 @@ build_all:
 build_layout:
 	@cd $(MOZ_SRC)\mozilla\.
 	nmake -f makefile.win all
+
+#//------------------------------------------------------------------------
+#// Utility stuff...
+#//------------------------------------------------------------------------
+
+#//------------------------------------------------------------------------
+# Verify that MOZ_SRC is set correctly
+#//------------------------------------------------------------------------
+
+# Check to see if it is set at all
+!if "$(MOZ_SRC)"!=""
+
+#
+# create a temp file at the root and make sure it is visible from MOZ_SRC
+#
+!if [copy $(MAKEDIR)\client.mak $(MAKEDIR)\xyzzy.tmp > NUL] == 0
+!endif
+
+!if !EXIST( $(MOZ_SRC)\mozilla\xyzzy.tmp )
+ERR_MESSAGE=$(ERR_MESSAGE)^
+MOZ_SRC isn't set correctly: [$(MOZ_SRC)\mozilla]!=[$(MAKEDIR)]
+!endif
+
+!if [del $(MAKEDIR)\xyzzy.tmp]
+!endif
+
+!else
+# MOZ_SRC isn't set at all
+ERR_MESSAGE=$(ERR_MESSAGE)^
+Environment variable MOZ_SRC isn't set.
+!endif
+
+#//------------------------------------------------------------------------
+# Verify that MOZ_BITS is set
+#//------------------------------------------------------------------------
+!if !defined(MOZ_BITS)
+ERR_MESSAGE=$(ERR_MESSAGE)^
+Environment variable MOZ_BITS isn't set.
+!endif
+
+!if !defined(MOZ_TOOLS)
+ERR_MESSAGE=$(ERR_MESSAGE)^
+Environment variable MOZ_TOOLS isn't set.
+!endif
+
+
+#//------------------------------------------------------------------------
+#// Display error 
+#//------------------------------------------------------------------------
+
+!if "$(ERR_MESSAGE)" != ""
+ERR_MESSAGE = ^
+client.mak:  ^
+$(ERR_MESSAGE) ^
+^
+client.mak: usage^
+^
+nmake -f client.mak [MOZ_BRANCH=<cvs_branch_name>] ^
+		    [MOZ_DATE=<cvs_date>]^
+		    [pull_and_build_all]^
+		    [pull_all]^
+		    [build_all]^
+^
+Environment variables:^
+^
+MOZ_BITS    set to 32^
+MOZ_SRC     set to the directory above mozilla or "$(MAKEDIR)\.."^
+MOZ_TOOLS   set to the directory containing the needed tools ^
+
+!ERROR $(ERR_MESSAGE)
+
+!endif