libxshmfence: update to 1.3.

Adam Jackson (2):
      configure: Nerf a thing
      Revert "configure: Nerf a thing"

Emil Velikov (1):
      autogen.sh: use quoted string variables

Matt Turner (1):
      libxshmfence 1.3

Michał Górny (1):
      Fix missing <limits.h> include for HAVE_UMTX branch of futex

Mihail Konev (1):
      autogen: add default patch prefix

Peter Hutterer (1):
      autogen.sh: use exec instead of waiting for configure to finish

Ross Burton (1):
      configure.ac: call AC_USE_SYSTEM_EXTENSIONS

(wiz)