Add obstack_free alias to _obstack_free

obstack.c: alias obstack_free to _obstack_free

Add obstack_printf to obstack.h header.

v1.2.2

obstack.h: add obstack_printf declaration.

Need to bump libobstack.so to .1

There was a change which replaced the obstack_free() function by a macro, thus we need to bump the solib version.

Update to 1.2

Use obstack.c and obstack.h from gcc-10.2.0 libiberty.
Add AC_CONFIG_HEADERS to configure.ac and make ./bootstrap.sh create config.h.in.

Fix build system user variables and add obstack_printf()

v1.1

Update version to 1.1

Initial version

v1.0

Version 1.0