Add missing header hints. ioperm() can now just work on Linux (since quite a long time actually)

1 files changed, 9 insertions, 1 deletions

diff --git a/hurd/porting/guidelines.mdwn b/hurd/porting/guidelines.mdwn
index 8dd27a52..030a4d06 100644
--- a/hurd/porting/guidelines.mdwn
+++ b/hurd/porting/guidelines.mdwn
@@ -219,7 +219,7 @@ These are not POSIX, `sys/types.h` and `stdint.h` should be used instead.
 
 ## <a name="iopl"> `iopl` </a>
 
-Not supported. Try to replace with `ioperm(0, 65536, 1)` (conditionned with `__GNU__` as that will not work in Linux).
+Not supported and actually very dangerous (permits userland to completely disable interruptions...). Replace with `ioperm(0, 65536, 1)`.
 
 ## <a name="iopl"> `semget`, `sem_open` </a>
 
@@ -269,3 +269,11 @@ With Python, you can use the [`errno` module](http://docs.python.org/library/err
       import errno
       err.errno == errno.ENOENT:
         ...
+
+## <a name="linux_headers"> Missing `linux/types.h`, `asm/types.h`, `linux/limits.h`, `asm/byteorder.h`, `sys/endian.h`, `asm/ioctl.h`, `asm/ioctls.h` </a>
+
+These are often used (from lame rgrep results) instead of their standard equivalents: `sys/types.h` (or `stdint.h` for fixed-size types), `limits.h`, `endian.h`, `sys/ioctl.h`.
+
+## <a name="linux_features"> Missing `sys/*.h`, `linux/*.h`</a>
+
+These are linuxish things, they may not have Hurd equivalents yet, better disable the code.