[PATCH] fix build issues in Hurd systems

[Flávio C. <fla...@gm...>]

Hello

There has been some issues when building clisp in Debian Hurd. See
https://buildd.debian.org/status/fetch.php?pkg=clisp&arch=hurd-i386&ver=1%3A2.49-10&stamp=1440769077
where
compilation fails with:

Bytes permanently allocated:             90,464
Bytes currently in use:               5,313,132
Bytes available until next GC:        1,328,283

*** - handle_fault error2 ! address = 0x7fff6884 not in
[0x67d05128,0x680a1000) !
SIGSEGV cannot be cured. Fault address = 0x7fff6884.
GC count: 128
Space collected by GC: 0 97002732
Run time: 5 800000
Real time: 6 392980
GC time: 0 620000
Permanently allocated: 90464 bytes.
Currently in use: 6641408 bytes.
Free space: 7 bytes.

*** - UNIX error 16776913: (ipc/mig) bad request message ID

*** - UNIX error 16776913: (ipc/mig) bad request message ID

*** - UNIX error 16776913: (ipc/mig) bad request message ID
make[1]: *** [interpreted.mem] Segmentation fault

This happens because the call to fsync (on stream.d) sets errno to
EMIG_BAD_ID, which crashes clisp. This patch fixes the problem by
defining IS_EINVAL_EXTRA for Hurd.

Best
Flávio