Makefile.am (nat_headers, [...]): Depend on .class files, not libgcj.jar.

	* Makefile.am (nat_headers, x_nat_headers): Depend on .class files, not
	libgcj.jar.
	(nat_files, x_nat_files): Build native files in subdirectories using
	the same dependency options as the java files.
	(gnu/gcj/runtime/FirstThread.h): Remove explicit rule and friend
	declarations.
	* configure.in: Put dependencies for .cc files in deps.mak.
	* Makefile.in: Rebuilt.
	* configure: Rebuilt.

From-SVN: r47471