Use -fdebug-default-version=4 for assembly files

-fdebug-default-version=5 is causing $TMPDIR to end up in the dwarf
debug data, which causes the buildbot results to be nondeterministic.
Pass -fdebug-default-version=4 for assembly files as a workaround.

Bug: 235105792
Test: lunch aosp_arm-userdebug && m libbase && llvm-dwarfdump --debug-line out/target/product/generic/symbols/system/lib/libbase.so
Change-Id: Ife04e3c898bbb1291f71b8365fbca854cd2d2b66

cc/cc_test.go

@@ -4076,7 +4076,7 @@ func TestIncludeDirectoryOrdering(t *testing.T) {
 		{
 			name:     "assemble",
 			src:      "foo.s",
-			expected: combineSlices(baseExpectedFlags, []string{"-D__ASSEMBLY__"}, expectedIncludes, lastIncludes),
+			expected: combineSlices(baseExpectedFlags, []string{"-D__ASSEMBLY__", "-fdebug-default-version=4"}, expectedIncludes, lastIncludes),
 		},
 	}
 

cc/compiler.go

@@ -495,6 +495,10 @@ func (compiler *baseCompiler) compilerFlags(ctx ModuleContext, flags Flags, deps
 
 	flags.Global.AsFlags = append(flags.Global.AsFlags, "-D__ASSEMBLY__")
 
+	// TODO(b/235105792): override global -fdebug-default-version=5, it is causing $TMPDIR to
+	// end up in the dwarf data for crtend_so.S.
+	flags.Global.AsFlags = append(flags.Global.AsFlags, "-fdebug-default-version=4")
+
 	flags.Global.CppFlags = append(flags.Global.CppFlags, tc.Cppflags())
 
 	flags.Global.YasmFlags = append(flags.Global.YasmFlags, tc.YasmFlags())