This patch makes sysdeps/unix/sysv/linux code assume the prlimit64
syscall is always available, given the minimum of a 3.2 kernel.
__ASSUME_PRLIMIT64, which in fact was no longer used, is removed.
Code conditional on __NR_prlimit64 being defined is made
unconditional. Fallback code for the case where prlimit64 produces an
ENOSYS error is removed, substantially simplifying some functions.
Tested for x86_64 and x86.
* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_PRLIMIT64):
Remove macro.
* sysdeps/unix/sysv/linux/getrlimit64.c (__getrlimit64): Assume
prlimit64 is always available and does not give an ENOSYS error.
* sysdeps/unix/sysv/linux/prlimit.c [__NR_prlimit64]: Make code
unconditional.
[!__NR_prlimit64]: Remove conditional code.
* sysdeps/unix/sysv/linux/setrlimit.c (__setrlimit): Assume
prlimit64 is always available and does not give an ENOSYS error.
* sysdeps/unix/sysv/linux/setrlimit64.c (__setrlimit64): Likewise.