cc: add min_sdk_version prop

min_sdk_version is the minimum version of the sdk that the compiled
artifacts will run against.

For example, when a module is used by two APEXes and their
min_sdk_versions are set to 29 and 30, then the module should support
both versions even if it is compiled against 30. Therefore,
min_sdk_version of the module needs to be set 29 in that case. In
general, this is set as the minimum value of min_sdk_vesions of APEXes.

For now, there's no build-time checks about this prop even if the prop
is set.

Bug: 145796956
Bug: 152655956
Bug: 153333044
Test: m nothing
Change-Id: I072ad8c317d2615e8b08e4e7ea2db8e7955b4b12
diff --git a/cc/cc.go b/cc/cc.go
index fdfc221..6e02b24 100644
--- a/cc/cc.go
+++ b/cc/cc.go
@@ -213,6 +213,9 @@
 	// two variants to be built, one for the platform and one for apps.
 	Sdk_version *string
 
+	// Minimum sdk version that the artifact should support when it runs as part of mainline modules(APEX).
+	Min_sdk_version *string
+
 	// If true, always create an sdk variant and don't create a platform variant.
 	Sdk_variant_only *bool