Debian patch for fixing build issues on JDK 10 and above.
In particular, 'javah' needs to replaced by 'javac -h' since 'javah'
has been removed due to JEP 313 (https://openjdk.java.net/jeps/313).

To support Javadoc generation with JDK 17 and above, the '-source 1.8'
option must be included in the arguments to 'javadoc'.  Otherwise, the
following error would be raised:

	src/gnu/io/LPRPort.java:373: error: invalid use of a restricted identifier 'yield'
				yield();
				^
	  (to invoke a method called yield, qualify the yield with a receiver or type name)

The original patch can be found at:
https://salsa.debian.org/java-team/rxtx/-/blob/6500bd55f265de7d2dfef68dc1df5d8b990f66c3/debian/patches/java10-compatibility.patch

Bug: https://bugs.gentoo.org/831394

--- a/Makefile.am
+++ b/Makefile.am
@@ -111,11 +111,6 @@
 $(CLASSES): $(javafiles) $(TOP)/Makefile
 	$(JAVAH_FIX)
 	$(JAVAC) $(javafiles)
-	$(JAVAH) `(for i in $(javahfiles);do \
-		if grep > /dev/null native.*\( $(SPATH)/gnu/io/$$i.java; then \
-			echo $(CLASSDIR).$$i; \
-		fi; \
-	done)`
 	$(JAR) cf $(JARTARGET) $(CLASSTOP)/*
 
 #  install librxtxSerial.so into the proper directory and copy $(JARTARGET) to its
--- a/configure.in
+++ b/configure.in
@@ -485,9 +485,9 @@
 	*)
 		find_java_native_include jni_md.h
 		JAVAH="\$(JPATH)/bin/javah -classpath \$(CLASSPATH) -d \$(DEST) -jni"
-		JAVAC="\$(JPATH)/bin/javac -classpath \$(CLASSPATH) -d \$(TOP)/ -O -source 1.8 -target 1.8"
+		JAVAC="\$(JPATH)/bin/javac -classpath \$(CLASSPATH) -d \$(TOP)/ -O -source 1.8 -target 1.8 -h \$(DEST)"
 		JAR="\$(JPATH)/bin/jar"
-		JAVADOC="\$(JPATH)/bin/javadoc"
+		JAVADOC="\$(JPATH)/bin/javadoc -source 1.8"
 		CFLAGS=$CFLAGS" -D_BSD_SOURCE"
 		;;
 	esac