dependencies.sh: check for java tools if classpath is enabled

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

support/dependencies/dependencies.sh

@@ -158,3 +158,11 @@ if grep ^BR2_TOOLCHAIN_BUILDROOT=y $CONFIG_FILE > /dev/null && \
        exit 1 ;
    fi
 fi
+if grep -q ^BR2_PACKAGE_CLASSPATH=y $CONFIG_FILE ; then
+    for prog in java javac jar; do
+	if ! which $prog > /dev/null ; then
+	    /bin/echo -e "\nYou must install '$prog' on your build machine\n" >&2
+	    exit 1
+	fi
+    done
+fi