Revert "Switch platform-NDK unwinder to LLVM libunwind.a prebuilt"

This reverts commit 29b9de083e9abe895c209a3c23c9fae345686c38.

Reason for revert: b/184095989

Change-Id: I11d90562e0703631258a5e9f1b2dc36f1702289a
diff --git a/cc/stl.go b/cc/stl.go
index 594231d..75fab17 100644
--- a/cc/stl.go
+++ b/cc/stl.go
@@ -188,7 +188,12 @@
 		if needsLibAndroidSupport(ctx) {
 			deps.StaticLibs = append(deps.StaticLibs, "ndk_libandroid_support")
 		}
-		deps.StaticLibs = append(deps.StaticLibs, "ndk_libunwind")
+		// TODO: Switch the NDK over to the LLVM unwinder for non-arm32 architectures.
+		if ctx.Arch().ArchType == android.Arm {
+			deps.StaticLibs = append(deps.StaticLibs, "ndk_libunwind")
+		} else {
+			deps.StaticLibs = append(deps.StaticLibs, "libgcc_stripped")
+		}
 	default:
 		panic(fmt.Errorf("Unknown stl: %q", stl.Properties.SelectedStl))
 	}