Add C2X timespec_getres

ISO C2X adds a timespec_getres function alongside the C11
timespec_get, with functionality similar to that of POSIX clock_getres
(including allowing a NULL pointer to be passed to the function).
Implement this function for glibc, similarly to the implementation of
timespec_get.

This includes a basic test like that of timespec_get, but no
documentation in the manual, given that TIME_UTC and timespec_get
aren't documented in the manual at all.  The handling of 64-bit time
follows that in timespec_get; people maintaining patch series for
64-bit time will need to update them accordingly (to export
__timespec_getres64, redirect calls in time.h and run the test for
_TIME_BITS=64).

Tested for x86_64 and x86, and (previous version; only testcase
differs) with build-many-glibcs.py.

44 files changed, 189 insertions, 2 deletions

diff --git a/NEWS b/NEWS
index a5631af920..266837bf2d 100644
--- a/NEWS
+++ b/NEWS
@@ -23,6 +23,8 @@ Major new features:
   /proc to be mounted.  However, different than fexecve, if the syscall is not
   supported by the kernel an error is returned instead of trying a fallback.
 
+* The ISO C2X function timespec_getres has been added.
+
 Deprecated and removed features, and other changes affecting compatibility:
 
 * The function pthread_mutex_consistent_np has been deprecated; programs
diff --git a/include/time.h b/include/time.h
index e0636132a6..4372bfbd96 100644
--- a/include/time.h
+++ b/include/time.h
@@ -28,6 +28,9 @@ libc_hidden_proto (__clock_gettime)
 extern __typeof (clock_settime) __clock_settime;
 libc_hidden_proto (__clock_settime)
 
+extern __typeof (clock_getres) __clock_getres;
+libc_hidden_proto (__clock_getres)
+
 extern __typeof (clock_nanosleep) __clock_nanosleep;
 libc_hidden_proto (__clock_nanosleep);
 
@@ -306,6 +309,7 @@ extern double __difftime (time_t time1, time_t time0);
 # define __clock_nanosleep_time64 __clock_nanosleep
 # define __clock_gettime64 __clock_gettime
 # define __timespec_get64 __timespec_get
+# define __timespec_getres64 __timespec_getres
 #else
 extern int __clock_nanosleep_time64 (clockid_t clock_id,
                                      int flags, const struct __timespec64 *req,
@@ -315,6 +319,8 @@ extern int __clock_gettime64 (clockid_t clock_id, struct __timespec64 *tp);
 libc_hidden_proto (__clock_gettime64)
 extern int __timespec_get64 (struct __timespec64 *ts, int base);
 libc_hidden_proto (__timespec_get64)
+extern int __timespec_getres64 (struct __timespec64 *ts, int base);
+libc_hidden_proto (__timespec_getres64)
 #endif
 
 #if __TIMESIZE == 64
diff --git a/sysdeps/mach/hurd/i386/libc.abilist b/sysdeps/mach/hurd/i386/libc.abilist
index fb2683edc2..49aa809366 100644
--- a/sysdeps/mach/hurd/i386/libc.abilist
+++ b/sysdeps/mach/hurd/i386/libc.abilist
@@ -2208,6 +2208,7 @@ GLIBC_2.34 __isnanf128 F
 GLIBC_2.34 __libc_start_main F
 GLIBC_2.34 _hurd_libc_proc_init F
 GLIBC_2.34 execveat F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/posix/clock_getres.c b/sysdeps/posix/clock_getres.c
index 0690ae8fcf..1eb26af6f7 100644
--- a/sysdeps/posix/clock_getres.c
+++ b/sysdeps/posix/clock_getres.c
@@ -62,6 +62,7 @@ __clock_getres (clockid_t clock_id, struct timespec *res)
 
   return retval;
 }
+libc_hidden_def (__clock_getres)
 
 versioned_symbol (libc, __clock_getres, clock_getres, GLIBC_2_17);
 /* clock_getres moved to libc in version 2.17;
diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
index c8920ed79b..bc051ba9f5 100644
--- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
@@ -2445,6 +2445,7 @@ GLIBC_2.34 sem_wait F
 GLIBC_2.34 thrd_detach F
 GLIBC_2.34 thrd_exit F
 GLIBC_2.34 thrd_join F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.34 tss_create F
 GLIBC_2.34 tss_delete F
 GLIBC_2.34 tss_get F
diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist
index dbc4a25aa3..3bea473d00 100644
--- a/sysdeps/unix/sysv/linux/alpha/libc.abilist
+++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist
@@ -2536,6 +2536,7 @@ GLIBC_2.34 sem_wait F
 GLIBC_2.34 thrd_detach F
 GLIBC_2.34 thrd_exit F
 GLIBC_2.34 thrd_join F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.34 tss_create F
 GLIBC_2.34 tss_delete F
 GLIBC_2.34 tss_get F
diff --git a/sysdeps/unix/sysv/linux/arc/libc.abilist b/sysdeps/unix/sysv/linux/arc/libc.abilist
index de790e8ecf..3461527c5a 100644
--- a/sysdeps/unix/sysv/linux/arc/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arc/libc.abilist
@@ -2204,6 +2204,7 @@ GLIBC_2.34 sem_wait F
 GLIBC_2.34 thrd_detach F
 GLIBC_2.34 thrd_exit F
 GLIBC_2.34 thrd_join F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.34 tss_create F
 GLIBC_2.34 tss_delete F
 GLIBC_2.34 tss_get F
diff --git a/sysdeps/unix/sysv/linux/arm/be/libc.abilist b/sysdeps/unix/sysv/linux/arm/be/libc.abilist
index 93ca2a5b28..7c3029a7e5 100644
--- a/sysdeps/unix/sysv/linux/arm/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/be/libc.abilist
@@ -311,6 +311,7 @@ GLIBC_2.34 sem_wait F
 GLIBC_2.34 thrd_detach F
 GLIBC_2.34 thrd_exit F
 GLIBC_2.34 thrd_join F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.34 tss_create F
 GLIBC_2.34 tss_delete F
 GLIBC_2.34 tss_get F
diff --git a/sysdeps/unix/sysv/linux/arm/le/libc.abilist b/sysdeps/unix/sysv/linux/arm/le/libc.abilist
index 935b2f99bb..24f5b202e8 100644
--- a/sysdeps/unix/sysv/linux/arm/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/le/libc.abilist
@@ -308,6 +308,7 @@ GLIBC_2.34 sem_wait F
 GLIBC_2.34 thrd_detach F
 GLIBC_2.34 thrd_exit F
 GLIBC_2.34 thrd_join F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.34 tss_create F
 GLIBC_2.34 tss_delete F
 GLIBC_2.34 tss_get F
diff --git a/sysdeps/unix/sysv/linux/clock_getres.c b/sysdeps/unix/sysv/linux/clock_getres.c
index 14e50fbdf2..d560cd7c48 100644
--- a/sysdeps/unix/sysv/linux/clock_getres.c
+++ b/sysdeps/unix/sysv/linux/clock_getres.c
@@ -79,6 +79,7 @@ __clock_getres (clockid_t clock_id, struct timespec *res)
   return retval;
 }
 #endif
+libc_hidden_def (__clock_getres)
 
 versioned_symbol (libc, __clock_getres, clock_getres, GLIBC_2_17);
 /* clock_getres moved to libc in version 2.17;
diff --git a/sysdeps/unix/sysv/linux/csky/libc.abilist b/sysdeps/unix/sysv/linux/csky/libc.abilist
index 32f14e48f6..85851c5fca 100644
--- a/sysdeps/unix/sysv/linux/csky/libc.abilist
+++ b/sysdeps/unix/sysv/linux/csky/libc.abilist
@@ -2388,6 +2388,7 @@ GLIBC_2.34 sem_wait F
 GLIBC_2.34 thrd_detach F
 GLIBC_2.34 thrd_exit F
 GLIBC_2.34 thrd_join F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.34 tss_create F
 GLIBC_2.34 tss_delete F
 GLIBC_2.34 tss_get F
diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist
index 4264754c4d..ede69c7ed5 100644
--- a/sysdeps/unix/sysv/linux/hppa/libc.abilist
+++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist
@@ -2341,6 +2341,7 @@ GLIBC_2.34 sem_wait F
 GLIBC_2.34 thrd_detach F
 GLIBC_2.34 thrd_exit F
 GLIBC_2.34 thrd_join F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.34 tss_create F
 GLIBC_2.34 tss_delete F
 GLIBC_2.34 tss_get F
diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist
index 519a060643..c883dc08bc 100644
--- a/sysdeps/unix/sysv/linux/i386/libc.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libc.abilist
@@ -2524,6 +2524,7 @@ GLIBC_2.34 sem_wait F
 GLIBC_2.34 thrd_detach F
 GLIBC_2.34 thrd_exit F
 GLIBC_2.34 thrd_join F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.34 tss_create F
 GLIBC_2.34 tss_delete F
 GLIBC_2.34 tss_get F
diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist
index 7a13ab08f6..38fb02e32b 100644
--- a/sysdeps/unix/sysv/linux/ia64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist
@@ -2377,6 +2377,7 @@ GLIBC_2.34 sem_wait F
 GLIBC_2.34 thrd_detach F
 GLIBC_2.34 thrd_exit F
 GLIBC_2.34 thrd_join F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.34 tss_create F
 GLIBC_2.34 tss_delete F
 GLIBC_2.34 tss_get F
diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
index 9b378e4447..8ee9648828 100644
--- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
@@ -312,6 +312,7 @@ GLIBC_2.34 sem_wait F
 GLIBC_2.34 thrd_detach F
 GLIBC_2.34 thrd_exit F
 GLIBC_2.34 thrd_join F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.34 tss_create F
 GLIBC_2.34 tss_delete F
 GLIBC_2.34 tss_get F
diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
index b6d0f57e9d..1c51cb41ec 100644
--- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
@@ -2467,6 +2467,7 @@ GLIBC_2.34 sem_wait F
 GLIBC_2.34 thrd_detach F
 GLIBC_2.34 thrd_exit F
 GLIBC_2.34 thrd_join F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.34 tss_create F
 GLIBC_2.34 tss_delete F
 GLIBC_2.34 tss_get F
diff --git a/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
index ac5d3656c7..f8b67cd170 100644
--- a/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
@@ -2439,6 +2439,7 @@ GLIBC_2.34 sem_wait F
 GLIBC_2.34 thrd_detach F
 GLIBC_2.34 thrd_exit F
 GLIBC_2.34 thrd_join F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.34 tss_create F
 GLIBC_2.34 tss_delete F
 GLIBC_2.34 tss_get F
diff --git a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
index 3c47c1c907..edac4a1bb4 100644
--- a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
@@ -2436,6 +2436,7 @@ GLIBC_2.34 sem_wait F
 GLIBC_2.34 thrd_detach F
 GLIBC_2.34 thrd_exit F
 GLIBC_2.34 thrd_join F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.34 tss_create F
 GLIBC_2.34 tss_delete F
 GLIBC_2.34 tss_get F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
index f9b4a578a9..db900c89ab 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
@@ -2432,6 +2432,7 @@ GLIBC_2.34 sem_wait F
 GLIBC_2.34 thrd_detach F
 GLIBC_2.34 thrd_exit F
 GLIBC_2.34 thrd_join F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.34 tss_create F
 GLIBC_2.34 tss_delete F
 GLIBC_2.34 tss_get F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
index 9e6c0e1c57..4e15f48b6c 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
@@ -2430,6 +2430,7 @@ GLIBC_2.34 sem_wait F
 GLIBC_2.34 thrd_detach F
 GLIBC_2.34 thrd_exit F
 GLIBC_2.34 thrd_join F
+GLIBC_2.34 timespec_getres F
 GLIBC_2.34 tss_create F
 GLIBC_2.34 tss_delete F
 GLIBC_2.34 tss_get F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
index d52f480650..616a6076f1 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist