Finish move of clock_* functions to libc. [BZ #24959]

In glibc 2.17, the functions clock_getcpuclockid, clock_getres,
clock_gettime, clock_nanosleep, and clock_settime were moved from
librt.so to libc.so, leaving compatibility stubs behind.  Now that the
dynamic linker no longer insists on finding versioned symbols in the
same library that originally defined them, we do not need the stubs
anymore, and this means we don't need GLIBC_PRIVATE __-prefix aliases
for most of the functions anymore either.  (clock_gettime still needs
one.)  For ports added before 2.17, libc.so needs to provide two
symbol versions for each, the default at GLIBC_2.17 plus a compat
version matching what librt had.

While I'm at it, move the clock_*.c files and their tests from rt/ to
time/.

72 files changed, 382 insertions, 243 deletions

diff --git a/ChangeLog b/ChangeLog
index 46fd5f2a24..7903eb9556 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,107 @@
+2019-09-04  Zack Weinberg  <zackw@panix.com>
+
+	[BZ #24959]
+	* rt/clock_getcpuclockid.c: Move to time/clock_getcpuclockid.c.
+	* rt/clock_getres.c: Move to time/clock_getres.c.
+	* rt/clock_gettime.c: Move to time/clock_gettime.c.
+	* rt/clock_nanosleep.c: Move to time/clock_nanosleep.c.
+	* rt/clock_settime.c: Move to time/clock_settime.c.
+	* rt/tst-clock.c: Move to time/tst-clock.c.
+	* rt/tst-clock2.c: Move to time/tst-clock2.c.
+	* rt/tst-clock_nanosleep.c: Move to time/tst-clock_nanosleep.c.
+	* rt/tst-cpuclock1.c: Move to time/tst-cpuclock1.c.
+	* rt/clock-compat.c: Delete file.
+
+	* time/clock_getcpuclockid.c
+	* time/clock_getres.c
+	* time/clock_gettime.c
+	* time/clock_nanosleep.c
+	* time/clock_settime.c
+	* sysdeps/posix/clock_getres.c
+	* sysdeps/unix/clock_gettime.c
+	* sysdeps/unix/clock_nanosleep.c
+	* sysdeps/unix/clock_settime.c
+	* sysdeps/unix/sysv/linux/clock_getcpuclockid.c
+	* sysdeps/unix/sysv/linux/clock_getres.c
+	* sysdeps/unix/sysv/linux/clock_gettime.c
+	* sysdeps/unix/sysv/linux/clock_nanosleep.c
+	* sysdeps/unix/sysv/linux/clock_settime.c: Define the function
+	defined by this file with default symbol version GLIBC_2_17,
+	and optionally a compatibility alias at symbol version GLIBC_2_2.
+	* include/time.h: Remove internal prototypes for clock_getres,
+	clock_nanosleep, and clock_getcpuclockid.
+
+	* sysdeps/unix/sysv/linux/clock_gettime.c: Prune includes.
+	Remove unused function realtime_gettime.
+
+	* rt/Makefile (clock-routines, routines): Remove variable.
+	(librt-routines): Remove clock-compat.
+	(tests): Remove tst-clock, tst-clock2, tst-clock_nanosleep,
+	and tst-cpuclock1.
+	* time/Makefile (routines): Add clock_getres, clock_gettime,
+	clock_settime, clock_getcpuclockid, and clock_nanosleep.
+	(tests): Add tst-clock, tst-clock2, tst-clock_nanosleep,
+	and tst-cpuclock1.
+
+	* rt/Versions (libc): Remove entire stanza.
+	(librt GLIBC_2.2): Remove all clock_* functions.
+	* time/Versions (libc GLIBC_2.2, libc GLIBC_2.17):
+	Add clock_getres, clock_gettime, clock_settime,
+	clock_getcpuclockid, and clock_nanosleep.
+	(libc GLIBC_PRIVATE): Add __clock_gettime.
+
+	* sysdeps/mach/hurd/i386/librt.abilist
+	* sysdeps/unix/sysv/linux/alpha/librt.abilist
+	* sysdeps/unix/sysv/linux/arm/be/librt.abilist
+	* sysdeps/unix/sysv/linux/arm/le/librt.abilist
+	* sysdeps/unix/sysv/linux/hppa/librt.abilist
+	* sysdeps/unix/sysv/linux/i386/librt.abilist
+	* sysdeps/unix/sysv/linux/ia64/librt.abilist
+	* sysdeps/unix/sysv/linux/m68k/coldfire/librt.abilist
+	* sysdeps/unix/sysv/linux/m68k/m680x0/librt.abilist
+	* sysdeps/unix/sysv/linux/microblaze/be/librt.abilist
+	* sysdeps/unix/sysv/linux/microblaze/le/librt.abilist
+	* sysdeps/unix/sysv/linux/mips/mips32/librt.abilist
+	* sysdeps/unix/sysv/linux/mips/mips64/librt.abilist
+	* sysdeps/unix/sysv/linux/powerpc/powerpc32/librt.abilist
+	* sysdeps/unix/sysv/linux/powerpc/powerpc64/be/librt.abilist
+	* sysdeps/unix/sysv/linux/s390/s390-32/librt.abilist
+	* sysdeps/unix/sysv/linux/s390/s390-64/librt.abilist
+	* sysdeps/unix/sysv/linux/sh/librt.abilist
+	* sysdeps/unix/sysv/linux/sparc/sparc32/librt.abilist
+	* sysdeps/unix/sysv/linux/sparc/sparc64/librt.abilist
+	* sysdeps/unix/sysv/linux/x86_64/64/librt.abilist