[pull] master from ruby:master

configure.ac

@@ -1746,7 +1746,6 @@ AS_IF([test "$GCC" = yes], [
 		    [rb_cv_gcc_atomic_builtins=no])])
     AS_IF([test "$rb_cv_gcc_atomic_builtins" = yes], [
 	AC_DEFINE(HAVE_GCC_ATOMIC_BUILTINS)
-	AC_CHECK_LIB([atomic], [__atomic_fetch_add_8])
 	AC_CACHE_CHECK([for 64bit __atomic builtins], [rb_cv_gcc_atomic_builtins_64], [
 	    AC_LINK_IFELSE([AC_LANG_PROGRAM([[@%:@include <stdint.h>
 			uint64_t atomic_var;]],

ruby_atomic.h

@@ -2,9 +2,6 @@
 #define INTERNAL_ATOMIC_H
 
 #include "ruby/atomic.h"
-#ifdef HAVE_STDATOMIC_H
-# include <stdatomic.h>
-#endif
 
 #define RUBY_ATOMIC_VALUE_LOAD(x) rbimpl_atomic_value_load(&(x), RBIMPL_ATOMIC_SEQ_CST)
 
@@ -79,9 +76,9 @@ rbimpl_atomic_u64_fetch_add(volatile rbimpl_atomic_uint64_t *ptr, uint64_t val)
     return InterlockedExchangeAdd64((volatile LONG64 *)ptr, val);
 #elif defined(__sun) && defined(HAVE_ATOMIC_H) && (defined(_LP64) || defined(_I32LPx))
     return atomic_add_64_nv(ptr, val) - val;
-#elif defined(HAVE_STDATOMIC_H)
-    return atomic_fetch_add_explicit((_Atomic uint64_t *)ptr, val, memory_order_seq_cst);
 #else
+    // TODO: stdatomic
+
     // Fallback using mutex for platforms without 64-bit atomics
     static rb_native_mutex_t lock = RB_NATIVE_MUTEX_INITIALIZER;
     rb_native_mutex_lock(&lock);

signal.c

@@ -949,6 +949,20 @@ sigsegv(int sig SIGINFO_ARG)
 }
 #endif
 
+#ifdef SIGABRT
+
+static sighandler_t default_sigabrt_handler;
+NORETURN(static ruby_sigaction_t sigabrt);
+
+static void
+sigabrt(int sig SIGINFO_ARG)
+{
+    check_reserved_signal("ABRT");
+    CHECK_STACK_OVERFLOW();
+    rb_bug_for_fatal_signal(default_sigabrt_handler, sig, SIGINFO_CTX, "Aborted" MESSAGE_FAULT_ADDRESS);
+}
+#endif
+
 #ifdef SIGILL
 
 static sighandler_t default_sigill_handler;
@@ -1558,6 +1572,10 @@ Init_signal(void)
         RB_ALTSTACK_INIT(GET_VM()->main_altstack, rb_allocate_sigaltstack());
         force_install_sighandler(SIGSEGV, (sighandler_t)sigsegv, &default_sigsegv_handler);
 #endif
+
+#ifdef SIGABRT
+        force_install_sighandler(SIGABRT, (sighandler_t)sigabrt, &default_sigabrt_handler);
+#endif
     }
 #ifdef SIGPIPE
     install_sighandler(SIGPIPE, sig_do_nothing);

spec/bundler/commands/exec_spec.rb

@@ -1020,7 +1020,7 @@ def bin_path(a,b,c)
     context "signal handling" do
       let(:test_signals) do
         open3_reserved_signals = %w[CHLD CLD PIPE]
-        reserved_signals = %w[SEGV BUS ILL FPE VTALRM KILL STOP EXIT]
+        reserved_signals = %w[SEGV BUS ILL FPE ABRT IOT VTALRM KILL STOP EXIT]
         bundler_signals = %w[INT]
 
         Signal.list.keys - (bundler_signals + reserved_signals + open3_reserved_signals)