Refining core interface, setROM() behavior validated

makefile

@@ -1,6 +1,6 @@
 # Java include directory pathnames
 # The Windows files need to be copied from a Windows JDK installation
-include_linux   = /usr/lib/jvm/java-13-openjdk-`\
+include_linux   = /usr/lib/jvm/java-14-openjdk-`\
     uname -r | sed 's/.*-//'`/include
 include_windows = jni-windows-include
 
@@ -10,12 +10,12 @@ default:
 	@echo
 	@echo "Planet Virtual Boy Emulator"
 	@echo "  https://www.planetvb.com/"
-	@echo "  July 30, 2020"
+	@echo "  August 3, 2020"
 	@echo
 	@echo "Intended build environment: Debian i386 or amd64"
 	@echo "  gcc-multilib"
 	@echo "  mingw-w64"
-	@echo "  openjdk-13-jdk"
+	@echo "  openjdk-14-jdk"
 	@echo
 	@echo "Usage: make <recipe>"
 	@echo "  Package recipes:"
@@ -74,7 +74,7 @@ core:
 desktop: clean_desktop
 	@echo "  Compiling Java desktop application"
 	@javac -sourcepath src/desktop --release 10 -Xlint:unchecked \
-        -d . src/desktop/Main.java
+        -h src/desktop/native -d . src/desktop/Main.java
 
 # Build all native modules
 .PHONY: native
@@ -112,6 +112,7 @@ clean_most: clean_desktop
 src/desktop/native/vue_NativeVUE.h: src/desktop/vue/NativeVUE.java
 	@javac -h src/desktop/native -sourcepath src/desktop -d . \
         src/desktop/vue/NativeVUE.java
+	@sleep 3
 
 # linux_x86
 .PHONY: lin32_pre
@@ -159,6 +160,6 @@ win64: win64_pre native_common
 .PHONY: native_common
 native_common:
 	@echo "  Building native module $(name)"
-	@$(prefix)gcc $(include) -Isrc/core/include $(gccargs) -s -shared -Os \
+	@$(prefix)gcc $(include) -Isrc/core/include $(gccargs) -s -shared -O2 \
         -fno-strict-aliasing \
         -o native/$(name)$(ext) src/desktop/native/native.c src/core/vue.c