examples: Fix 'make' failures in VPATH builds.

examples: Fix 'make' failures in VPATH builds.

* gettext-tools/examples/hello-java*/Makefile.am (hello_RESOURCES,
MAINTAINERCLEANFILES): Remove variables.
(hello.jar): Use two jar commands, to combine .class files from the build dir
with .properties files from the source dir.
* gettext-tools/examples/hello-java*/po/Makefile.am (update-properties,
update-classes): Reference the .pot file in the source dir, not in the build
dir.
(echo-catalogs): Include the fallback catalog.
* gettext-tools/examples/hello-pascal/Makefile.am (hello_SOURCES): Add $(srcdir)
prefix.
(hello$(EXEEXT)): Use -o option to specify where the object file and the
executable file shall be created.