Fix use of uninstalled header by installed headers

* libguile/Makefile.am (libpath.h): Remove definition of
  SCM_EFFECTIVE_VERSION, which is defined in version.h.
* libguile/extensions.h: Remove libpath.h inclusion, as it's not
  installed.
* libguile/atomic.c:
* libguile/bytevectors.c:
* libguile/control.c:
* libguile/fdes-finalizers.c:
* libguile/foreign-object.c:
* libguile/foreign.c:
* libguile/fports.c:
* libguile/frames.c:
* libguile/goops.c:
* libguile/i18n.c:
* libguile/instructions.c:
* libguile/intrinsics.c:
* libguile/ioext.c:
* libguile/load.c:
* libguile/loader.c:
* libguile/poll.c:
* libguile/ports.c:
* libguile/posix.c:
* libguile/programs.c:
* libguile/r6rs-ports.c:
* libguile/srfi-1.c:
* libguile/srfi-60.c:
* libguile/threads.c:
* libguile/unicode.c:
* libguile/vm.c:
* libguile/weak-vector.c: Include version.h for the
  SCM_EFFECTIVE_VERSION definition.

libguile/unicode.c

@@ -34,6 +34,7 @@
 #include "extensions.h"
 #include "gsubr.h"
 #include "strings.h"
+#include "version.h"
 
 #include "unicode.h"