Readd support for PRODUCT_RELEASE_CONFIG_MAPS

This allows product config to determine what build flags are present in
a product's build, as well as their value.

As product config moves to a declarative specification, this can be
handled with less unnecessary work.

Bug: b/302593603, b/308849337, b/309477343
Test: manual
Change-Id: Ic0551990864bba6d03b6bf49fcfd4ae2523d9c6d
diff --git a/ui/build/dumpvars.go b/ui/build/dumpvars.go
index efe7478..d364542 100644
--- a/ui/build/dumpvars.go
+++ b/ui/build/dumpvars.go
@@ -191,6 +191,9 @@
 		"TARGET_BUILD_APPS",
 		"TARGET_BUILD_UNBUNDLED",
 
+		// Additional release config maps
+		"PRODUCT_RELEASE_CONFIG_MAPS",
+
 		// compiler wrappers set up by make
 		"CC_WRAPPER",
 		"CXX_WRAPPER",