Bring java support closer to current version of make

Make the javac arguments match what is used by make, and export them
back to make.  A future change will switch make to use the the
exported ones.

This makes a dx.jar compiled with soong have identical class files
as one compiled with make.

Test: manual
Change-Id: Ia5196f1f42bc564e99de22e32e72fd2930e9fbae
diff --git a/java/config/makevars.go b/java/config/makevars.go
index 6702454..ec0d939 100644
--- a/java/config/makevars.go
+++ b/java/config/makevars.go
@@ -26,4 +26,14 @@
 
 func makeVarsProvider(ctx android.MakeVarsContext) {
 	ctx.Strict("TARGET_DEFAULT_JAVA_LIBRARIES", strings.Join(DefaultLibraries, " "))
+
+	ctx.Strict("DEFAULT_JAVA_LANGUAGE_VERSION", "${DefaultJavaVersion}")
+
+	ctx.Strict("ANDROID_JAVA_HOME", "${JavaHome}")
+	ctx.Strict("ANDROID_JAVA_TOOLCHAIN", "${JavaToolchain}")
+	ctx.Strict("JAVA", "${JavaCmd}")
+	ctx.Strict("JAVAC", "${JavacCmd}")
+	ctx.Strict("JAR", "${JarCmd}")
+	ctx.Strict("JAVADOC", "${JavadocCmd}")
+	ctx.Strict("COMMON_JDK_FLAGS", "${CommonJdkFlags}")
 }