[build] Create libguile/version.h using the configure script.

[build] Create libguile/version.h using the configure script.

* configure.ac (AC_CONFIG_FILES): Add libguile/version.h.

* libguile/Makefile.am (version.h): Delete target.
  (EXTRA_DIST): Remove version.h.in.
  (BUILT_SOURCES): Remove version.h.
  (MOSTLYCLEANFILES): Remove version.h, version.h.tmp.
* libguile/version.h.in (SCM_MAJOR_VERSION): Use conventional
  @VAR@ instead of @-VAR-@ for ‘GUILE_MAJOR_VERSION’.
  (SCM_MINOR_VERSION, SCM_MICRO_VERSION, SCM_EFFECTIVE_VERSION): Likewise
  for ‘GUILE_MINOR_VERSION’, ‘GUILE_MICRO_VERSION’, ‘GUILE_EFFECTIVE_VERSION’.