Update Android port

* exec/config.h.in: Autoheader.
* exec/configure.ac: Check for siginfo_t.si_syscall.
* exec/trace.c (exec_waitpid): If SIGSYS is received, and caused by
seccomp, drop it should the call number be the invalid system call
used by Emacs.

exec/config.h.in

@@ -58,6 +58,9 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>. */
 /* Define to 1 if process_vm_readv is available. */
 #undef HAVE_PROCESS_VM
 
+/* Define to 1 if `si_syscall' is a member of `siginfo_t'. */
+#undef HAVE_SIGINFO_T_SI_SYSCALL
+
 /* Define to 1 if stdbool.h conforms to C99. */
 #undef HAVE_STDBOOL_H
 

exec/configure.ac

@@ -73,6 +73,10 @@ AC_CHECK_FUNC([process_vm_readv],
 #include <sys/uio.h>
       ]])])])
 AC_CHECK_HEADERS([sys/param.h sys/uio.h])
+AC_CHECK_MEMBERS([siginfo_t.si_syscall], [], [],
+  [[
+#include <signal.h>
+  ]])
 
 AH_BOTTOM([
 #ifdef HAVE_STDBOOL_H

exec/trace.c

@@ -1174,6 +1174,31 @@ exec_waitpid (pid_t pid, int *wstatus, int options)
 	  ptrace (PTRACE_SYSCALL, pid, 0, 0);
 	  return -1;
 
+#ifdef SIGSYS
+	case SIGSYS:
+	  if (ptrace (PTRACE_GETSIGINFO, pid, 0, &siginfo))
+	    return -1;
+
+	  /* Continue the process until the next syscall, but don't
+	     pass through the signal if an emulated syscall led to
+	     it.  */
+#ifdef HAVE_SIGINFO_T_SI_SYSCALL
+#ifndef __arm__
+	  ptrace (PTRACE_SYSCALL, pid, 0, ((siginfo.si_code == SYS_SECCOMP
+					    && siginfo.si_syscall == -1)
+					   ? 0 : status));
+#else /* __arm__ */
+	  ptrace (PTRACE_SYSCALL, pid, 0, ((siginfo.si_code == SYS_SECCOMP
+					    && siginfo.si_syscall == 222)
+					   ? 0 : status));
+#endif /* !__arm__ */
+#else /* !HAVE_SIGINFO_T_SI_SYSCALL */
+	  /* Drop this signal, since what caused it is unknown.  */
+	  ptrace (PTRACE_SYSCALL, pid, 0, 0);
+#endif /* HAVE_SIGINFO_T_SI_SYSCALL */
+	  return -1;
+#endif /* SIGSYS */
+
 	default:
 	  /* Continue the process until the next syscall.  */
 	  ptrace (PTRACE_SYSCALL, pid, 0, status);