Use llvm-{objcopy,strip} when clang lld is used.

* Pass LLVM_{OBJCOPY,STRIP} to makefile rules.
* strip.sh is used only in soong-only mode.
  It will use llvm-strip and  and llvm-objcopy
  when --use-llvm-strip is given.
  Keep flags of strip.sh in alphabetic order.
* Tested build/soong/scripts/build-ndk-prebuilts.sh
  by adding "UseClangLld": true, to soong.variables file.

Bug: 80093681
Test: build/soong/scripts/build-ndk-prebuilts.sh
Change-Id: I612267304eea434c7a33cc086b27b577d5f64094
diff --git a/cc/binary.go b/cc/binary.go
index 00fda06..04b912a 100644
--- a/cc/binary.go
+++ b/cc/binary.go
@@ -318,6 +318,10 @@
 	builderFlags := flagsToBuilderFlags(flags)
 
 	if binary.stripper.needsStrip(ctx) {
+		// b/80093681, GNU strip/objcopy bug.
+		// Use llvm-{strip,objcopy} when clang lld is used.
+		builderFlags.stripUseLlvmStrip =
+			flags.Clang && binary.baseLinker.useClangLld(ctx)
 		strippedOutputFile := outputFile
 		outputFile = android.PathForModuleOut(ctx, "unstripped", fileName)
 		binary.stripper.strip(ctx, outputFile, strippedOutputFile, builderFlags)