Bump our macOS target version to 10.9.

https://developer.apple.com/documentation/xcode/notarizing_macos_software_before_distribution/resolving_common_notarization_issues
says "notarization only works for binaries linked against macOS 10.9
or later".

Test: N/A
Bug: http://b/143105198
Change-Id: If66f81caa2f074bf70a75094da578295aa9f58ad
diff --git a/cc/config/x86_darwin_host.go b/cc/config/x86_darwin_host.go
index 63b9d48..000228d 100644
--- a/cc/config/x86_darwin_host.go
+++ b/cc/config/x86_darwin_host.go
@@ -100,7 +100,7 @@
 	pctx.VariableFunc("macSdkRoot", func(ctx android.PackageVarContext) string {
 		return xcrunSdk(ctx, "--show-sdk-path")
 	})
-	pctx.StaticVariable("macMinVersion", "10.8")
+	pctx.StaticVariable("macMinVersion", "10.9")
 	pctx.VariableFunc("MacArPath", func(ctx android.PackageVarContext) string {
 		return xcrun(ctx, "--find", "ar")
 	})