rust: Rust sanitized snapshots variations

This adds support for correctly handling Rust sanitized snapshots,
ensuring they only have one variation.

The presence of multiple variations were causing build failures
when a rust_fuzz module for host was defined and a snapshot
build was requested.

This also sets -Z link-native-libraries=no on host modules
(in addition to device modules) to avoid emitting extra linkage
flags due to link attributes.

Bug: 282897366
Test: SOONG_SDK_SNAPSHOT_USE_SRCJAR=true m
Change-Id: Idf980c29145f11c530ad635a4eb5b01a1730ac24
diff --git a/rust/fuzz.go b/rust/fuzz.go
index 235f517..4c04ce8 100644
--- a/rust/fuzz.go
+++ b/rust/fuzz.go
@@ -60,6 +60,25 @@
 	fuzz.binaryDecorator.baseCompiler.dir64 = "fuzz"
 	fuzz.binaryDecorator.baseCompiler.location = InstallInData
 	module.sanitize.SetSanitizer(cc.Fuzzer, true)
+
+	// The fuzzer runtime is not present for darwin or bionic host modules, so disable rust_fuzz modules for these.
+	android.AddLoadHook(module, func(ctx android.LoadHookContext) {
+
+		extraProps := struct {
+			Target struct {
+				Darwin struct {
+					Enabled *bool
+				}
+				Linux_bionic struct {
+					Enabled *bool
+				}
+			}
+		}{}
+		extraProps.Target.Darwin.Enabled = cc.BoolPtr(false)
+		extraProps.Target.Linux_bionic.Enabled = cc.BoolPtr(false)
+		ctx.AppendProperties(&extraProps)
+	})
+
 	module.compiler = fuzz
 	return module, fuzz
 }