Alpha: Fix the RLIM_INFINITY and RLIM64_INFINITY constants

Alpha: Fix the RLIM_INFINITY and RLIM64_INFINITY constants

Fix the RLIM_INFINITY and RLIM64_INFINITY constants on alpha to match
the kernel one and all other architectures. Change the getrlimit,
getrlimit64, setrlimit, setrlimit64 into old compat symbols, and provide
the Linux generic functions as GLIBC_2_27 version.

Changelog:
	* sysdeps/unix/sysv/linux/getrlimit64.c [USE_VERSIONED_RLIMIT]: Do not
	define getrlimit and getrlimit64 as weak aliases of __getrlimit64.
	Define __GI_getrlimit64 as weak alias of __getrlimit64.
	[__RLIM_T_MATCHES_RLIM64_T]: Do not redefine SHLIB_COMPAT, use #elif
	instead.
	* sysdeps/unix/sysv/linux/setrlimit64.c [USE_VERSIONED_RLIMIT]: Do not
	define setrlimit and setrlimit64 as weak aliases of __setrlimit64.
	* sysdeps/unix/sysv/linux/alpha/bits/resource.h (RLIM_INFINITY,
	RLIM64_INFINITY): Fix values to match the kernel ones.
	* sysdeps/unix/sysv/linux/alpha/getrlimit64.c: Define
	USE_VERSIONED_RLIMIT.  Rename __getrlimit64 into __old_getrlimit64 and
	provide it as getrlimit@@GLIBC_2_0 and getrlimit64@@GLIBC_2_1.  Add a
	__getrlimit64 function and provide it as getrlimit@@GLIBC_2_27 and
	getrlimit64@@GLIBC_2_27.
	* sysdeps/unix/sysv/linux/alpha/setrlimit64.c: Ditto with setrlimit
	and setrlimit64.
	* sysdeps/unix/sysv/linux/alpha/libc.abilist (GLIBC_2.27): Add
	getrlimit, setrlimit, getrlimit64 and setrlimit64.
	* sysdeps/unix/sysv/linux/alpha/Versions (libc): Add getrlimit,
	setrlimit, getrlimit64 and setrlimit64.