Move javac and javah to make variables.

japi/Makefile.in

@@ -34,6 +34,8 @@ INSTALL = @INSTALL@
 INSTALL_PROGRAM = @INSTALL_PROGRAM@
 INSTALL_DATA = @INSTALL_DATA@
 RANLIB = @RANLIB@
+JAVAC=javac
+JAVAH=javah -jni
 
 CC = @CC@
 #	We'll need something in 'configure' for the Java includes.
@@ -64,10 +66,10 @@ CLASSES = SaneDevice.class SaneOption.class SaneRange.class Sane.class \
 .SUFFIXES: .c .o .h .la .lo .java .class
 
 .java.class:
-	javac $<
+	$(JAVAC) $<
 
 .class.h:
-	javah -jni $*
+	$(JAVAH) $*
 
 %.lo:	%.c
 	@$(LIBTOOL) $(MCOMP) $(COMPILE) $<