Handle abort call for -fexceptions call

clang might generate an abort call when cleanup functions (set by
__attribute__ ((cleanup)) calls functions not marked as nothrow.
We can mitigate by marking some internal functions as __THROW,
but it is not possible for functions that issue used-provided
callbacks (for instance pthread_once).

elf/Makefile

@@ -1476,6 +1476,11 @@ rtld-stubbed-symbols += \
   __GI___vsyslog_chk \
   # rtld-stubbed-symbols
 
+# clang might generate an abort call for cleanup functions.
+rtld-stubbed-symbols += \
+  __GI_abort \
+  # rtld-stubbed-symbols
+
 ifeq ($(have-ssp),yes)
 # rtld is not built with the stack protector, so these references will
 # go away in the rebuilds.

sysdeps/generic/symbol-hacks.h

@@ -30,6 +30,13 @@ asm ("strcpy = __GI_strcpy");
 asm ("strncpy = __GI_strncpy");
 asm ("strcat = __GI_strcat");
 
+/* clang might generate an abort call when cleanup functions (set by
+   __attribute__ ((cleanup)) calls functions not marked as nothrow.
+   We can mitigate by marking some internal functions as __THROW,
+   but it is not possible for functions that issue used-provided
+   callbacks (for instance pthread_once).  */
+asm ("abort = __GI_abort");
+
 /* Some targets do not use __stack_chk_fail_local.  In libc.so,
    redirect __stack_chk_fail to a hidden reference
    __stack_chk_fail_local, to avoid the PLT reference.

sysdeps/nptl/lowlevellock.h

@@ -125,9 +125,9 @@ libc_hidden_proto (__lll_lock_wait)
 #define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)
 
 
-extern void __lll_lock_wake_private (int *futex);
+extern void __lll_lock_wake_private (int *futex) __THROW;
 libc_hidden_proto (__lll_lock_wake_private)
-extern void __lll_lock_wake (int *futex, int private);
+extern void __lll_lock_wake (int *futex, int private) __THROW;
 libc_hidden_proto (__lll_lock_wake)
 
 /* This is an expression rather than a statement even though its value is