The following lines are used in 161 makefiles:

-----------------------------------------------------------------------
# Strings to replace in man pages
XORGRELSTRING = @PACKAGE_STRING@
  XORGMANNAME = X Version 11

SED = sed

MAN_SUBSTS = \
        -e 's|__vendorversion__|"$(XORGRELSTRING)" "$(XORGMANNAME)"|' \
        -e 's|__appmansuffix__|$(APP_MAN_SUFFIX)|g'
-------------------------------------------------------------------------

By adding to XORG_MANPAGE_SECTIONS macro:
  AC_REQUIRE([AC_PROG_SED])
  XORG_MAN_NAME='X Version 11'
  AC_SUBST([XORG_MAN_NAME])

we can write in all these makefiles:

-----------------------------------------------------------------------
# Strings to replace in man pages
MAN_SUBSTS = \
        -e 's|__vendorversion__|"$(PACAKGE_STRING)" "$(XORG_MAN_NAME)"|' \
        -e 's|__appmansuffix__|$(APP_MAN_SUFFIX)|g'
--------------------------------------------------------------------------

AC_PROG_SED will test for an appropriate sed program that does not truncate lines and set the SED variable accordingly.