task_self on hurd

[Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>]

Dear Hurd porters,

GAP FTBFS on hurd probably because te code attempt to use Mach memory
management functions instead of POSIX one:
<https://buildd.debian.org/status/fetch.php?pkg=gap&arch=hurd-i386&ver=4r6p5-1&stamp=1378729845>

../../src/system.c: In function 'SyAllocBags':
../../src/system.c:1373:13: warning: implicit declaration of function 'task_self' [-Wimplicit-function-declaration]
             if ( vm_allocate(task_self(),&syBase,size*1024,TRUE) == KERN_SUCCESS ) {
             ^
None of the hurd porterbox seems to be available currently so I do not know more about the
issue.  So I ask, is there a task_self() on hurd ?  

Cheers,
Bill.