Introduce hacks to make it possible to build the standard library in the Java

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Introduce hacks to make it possible to build the standard library in the Java
grade, even though sub-modules aren't yet supported by the Java backend.

library/Mmakefile:
        Copy submodule source files into package directories as expected by
        javac, e.g. thread.mvar.java -> thread_/mvar.java

        Make `jars' target include source files in package directories.

library/Mmakefile

@@ -248,17 +248,25 @@ endif
 # likewise use `mr_enum'.  Since Java implementations often assume that
 # a class foo is located in a file foo.java, we similarly mangle the
 # Java file names for these standard library modules.
+# We also need to fix up the file names for nested modules.
 JAVAS = ` echo $($(STD_LIB_NAME).javas) | sed \
 		-e 's/ int.java/ mr_int.java/' \
 		-e 's/ float.java/ mr_float.java/' \
 		-e 's/ char.java/ mr_char.java/' \
-		-e 's/ enum.java/ mr_enum.java/' `
+		-e 's/ enum.java/ mr_enum.java/' \
+		-e 's: bit_buffer.read.java: bit_buffer_/read.java:' \
+		-e 's: bit_buffer.write.java: bit_buffer_/write.java:' \
+		-e 's: stream.string_writer.java: stream_/string_writer.java:' \
+		-e 's: string.builder.java: string_/builder.java:' \
+		-e 's: thread.channel.java: thread_/channel.java:' \
+		-e 's: thread.mvar.java: thread_/mvar.java:' \
+		-e 's: thread.semaphore.java: thread_/semaphore.java:' `
 
 # We need to invoke javac on all of the classes at the same time,
 # rather than compiling them separately.  This is needed because
 # otherwise javac doesn't handle cyclic dependencies between different
 # modules.
-classes: javas java_symlinks
+classes: javas java_symlinks java_subdir_copies
 	$(JAVAC) $(ALL_JAVACFLAGS) $(JAVAS)
 
 # javac expects to find the sources for symbols named mercury.* in
@@ -272,6 +280,22 @@ java_symlinks:
 	[ -d mercury ] || ln -s . mercury
 	[ -d runtime ] || ln -s $(MERCURY_DIR)/java/runtime .
 
+# Mercury doesn't yet put .java files in the directory hierarchies that Java
+# expects.  For now we copy a few files manually.
+.PHONY: java_subdir_copies
+java_subdir_copies:
+	[ -d bit_buffer_ ] || mkdir bit_buffer_
+	[ -d stream_ ] || mkdir stream_
+	[ -d string_ ] || mkdir string_
+	[ -d thread_ ] || mkdir thread_
+	cp bit_buffer.read.java bit_buffer_/read.java
+	cp bit_buffer.write.java bit_buffer_/write.java
+	cp stream.string_writer.java stream_/string_writer.java
+	cp string.builder.java string_/builder.java
+	cp thread.channel.java thread_/channel.java
+	cp thread.mvar.java thread_/mvar.java
+	cp thread.semaphore.java thread_/semaphore.java
+
 # Once all of the library classes have been compiled, we put them in a single
 # jar file.  At this point we also add the runtime classes to a jar file.
 # Note that this stage makes use of the symbolic links created earlier to
@@ -286,7 +310,11 @@ JARS = $(STD_LIB_NAME).jar $(RT_LIB_NAME).jar
 # any architecture-specific objects.
 .PHONY:	jars
 jars:	classes
-	$(JAR) $(JAR_CREATE_FLAGS) $(STD_LIB_NAME).jar mercury/*.class
+	$(JAR) $(JAR_CREATE_FLAGS) $(STD_LIB_NAME).jar mercury/*.class \
+		mercury/bit_buffer_/*.class \
+		mercury/stream_/*.class \
+		mercury/string_/*.class \
+		mercury/thread_/*.class
 	$(JAR) $(JAR_CREATE_FLAGS) $(RT_LIB_NAME).jar mercury/runtime/*.class
 	-+cd mercury/runtime && mmake $(NATIVE_SO)
 	-cp mercury/runtime/$(NATIVE_SO) .