Supress warnings about unset classpath

I get the below warning for every single jar file without this patch.
warning: [options] bootstrap class path not set in conjunction with
-source 1.5
1 warning

Change-Id: I71c01aeea993640f1ec86fe1d8a977656861358d

config_host.mk.in

@@ -257,6 +257,7 @@ export JAVACOMPILER=@JAVACOMPILER@
 export JAVADOC=@JAVADOC@
 export JAVADOCISGJDOC=@JAVADOCISGJDOC@
 export JAVAIFLAGS=@JAVAIFLAGS@
+export JAVA_CLASSPATH_NOT_SET=@JAVA_CLASSPATH_NOT_SET@
 export JAVAINTERPRETER=@JAVAINTERPRETER@
 @x_JAVALIB@ export JAVALIB=@JAVALIB@
 export JAVA_HOME=@JAVA_HOME@

configure.ac

@@ -6068,6 +6068,10 @@ you must use the "--with-jdk-home" configure option explicitly])
             if test "$_jdk_ver" -lt 10500; then
                 AC_MSG_ERROR([JDK is too old, you need at least 1.5])
             fi
+            if test "$_jdk_ver" -gt 10600; then
+                JAVA_CLASSPATH_NOT_SET="1"
+            fi
+
             AC_MSG_RESULT([checked (JDK $_jdk)])
             JAVA_HOME=`echo $JAVAINTERPRETER | $SED -n "s,//*bin//*java,,p"`
             if test "$_os" = "WINNT"; then
@@ -6613,6 +6617,7 @@ AC_SUBST(JAVACOMPILER)
 AC_SUBST(JAVADOC)
 AC_SUBST(JAVAINTERPRETER)
 AC_SUBST(JAVAIFLAGS)
+AC_SUBST(JAVA_CLASSPATH_NOT_SET)
 AC_SUBST(JAVA_HOME)
 AC_SUBST(JAVA_SOURCE_VER)
 AC_SUBST(JAVA_TARGET_VER)

solenv/gbuild/JavaClassSet.mk

@@ -27,7 +27,8 @@
 #*************************************************************************
 
 gb_JavaClassSet_JAVACCOMMAND := $(ICECREAM_RUN) $(JAVACOMPILER) $(JAVAFLAGS) \
-    -source $(JAVA_SOURCE_VER) -target $(JAVA_TARGET_VER)
+    -source $(JAVA_SOURCE_VER) -target $(JAVA_TARGET_VER) \
+    $(if $(JAVA_CLASSPATH_NOT_SET),-Xlint:-options)
 gb_JavaClassSet_JAVACDEBUG :=
 
 # Enforces correct dependency order for possibly generated stuff: