Build failure for in-tree xorg

[Paul Goyette <paul%whooppee.com@localhost>]

With up-to-date sources, and a totally clean $OBJDIR I am getting

/build/netbsd-local/xsrc/external/mit/xf86-video-chips/dist/src/ct_driver.c: In function 'chipsMapMem':
/build/netbsd-local/xsrc/external/mit/xf86-video-chips/dist/src/ct_driver.c:6870:14: error: implicit declaration of function 'mmap' [-Werror=implicit-function-declaration]
    *result = mmap(NULL,
              ^
/build/netbsd-local/xsrc/external/mit/xf86-video-chips/dist/src/ct_driver.c:6872:15: error: 'PROT_READ' undeclared (first use in this function)
               PROT_READ | PROT_WRITE,
               ^
/build/netbsd-local/xsrc/external/mit/xf86-video-chips/dist/src/ct_driver.c:6872:15: note: each undeclared identifier is reported only once for each function it appears in
/build/netbsd-local/xsrc/external/mit/xf86-video-chips/dist/src/ct_driver.c:6872:27: error: 'PROT_WRITE' undeclared (first use in this function)
               PROT_READ | PROT_WRITE,
                           ^
/build/netbsd-local/xsrc/external/mit/xf86-video-chips/dist/src/ct_driver.c:6873:15: error: 'MAP_SHARED' undeclared (first use in this function)
               MAP_SHARED,
               ^
/build/netbsd-local/xsrc/external/mit/xf86-video-chips/dist/src/ct_driver.c:6876:22: error: 'MAP_FAILED' undeclared (first use in this function)
    err = (*result == MAP_FAILED);
                      ^
...






+------------------+--------------------------+------------------------+
| Paul Goyette     | PGP Key fingerprint:     | E-mail addresses:      |
| (Retired)        | FA29 0E3B 35AF E8AE 6651 | paul at whooppee.com   |
| Kernel Developer | 0786 F758 55DE 53BA 7731 | pgoyette at netbsd.org |
+------------------+--------------------------+------------------------+