Re: udev, input/linux.h and cross compilation

[Kay Sievers <kay.sievers@vrfy.org>]

On Fri, Jan 22, 2010 at 15:02, Dan Nicholson <dbn.lists@gmail.com> wrote:
> On Thu, Jan 21, 2010 at 5:29 PM, Paul Bender <pebender@san.rr.com> wrote:
>> On 1/21/2010 3:00 AM, Martin Pitt wrote:
>>>
>>> echo '#include<linux/input.h>' | cpp -M | xargs -n1 | grep linux/input.h
>>
>> I believe that would work once cpp is replaced with $ac_cpp so that the
>> correct cpp is used (the one pointed to by $CPP) and the correct cpp flags
>> are used (the flags in $CPPFLAGS). However, it adds dependencies on grep and
>> xargs, both of which would need to be tested for.
>
> I'm pretty sure libtool is already using grep. However, here's an
> alternative just using sed:
>
> echo '#include <linux/input.h>' | cpp -M | sed -n
> '/linux\/input.h/s,.* \(.*linux/input.h\).*,\1,p'

Yeah, looks fine. I ended up with:
  $ echo '#include <linux/errno.h>'| \
    cpp -E| \
    sed '/linux\/errno.h/!d; s:.*"\(.*\)/linux/errno.h".*:\1:; /.*/q'
  /usr/include

to find the prefix for the current system include we can use in the Makefile.

Kay