Index: lldb/cmake/modules/LLDBGenerateConfig.cmake
===================================================================
--- lldb/cmake/modules/LLDBGenerateConfig.cmake
+++ lldb/cmake/modules/LLDBGenerateConfig.cmake
@@ -9,7 +9,6 @@
 check_symbol_exists(ppoll poll.h HAVE_PPOLL)
 check_symbol_exists(ptsname_r stdlib.h HAVE_PTSNAME_R)
 set(CMAKE_REQUIRED_DEFINITIONS)
-check_symbol_exists(sigaction signal.h HAVE_SIGACTION)
 check_cxx_symbol_exists(accept4 "sys/socket.h" HAVE_ACCEPT4)
 
 check_include_file(termios.h HAVE_TERMIOS_H)
Index: lldb/include/lldb/Host/Config.h.cmake
===================================================================
--- lldb/include/lldb/Host/Config.h.cmake
+++ lldb/include/lldb/Host/Config.h.cmake
@@ -22,8 +22,6 @@
 
 #cmakedefine01 HAVE_PTSNAME_R
 
-#cmakedefine01 HAVE_SIGACTION
-
 #cmakedefine01 HAVE_PROCESS_VM_READV
 
 #cmakedefine01 HAVE_NR_PROCESS_VM_READV
Index: lldb/include/lldb/Host/MainLoop.h
===================================================================
--- lldb/include/lldb/Host/MainLoop.h
+++ lldb/include/lldb/Host/MainLoop.h
@@ -95,7 +95,7 @@
 
   struct SignalInfo {
     std::list<Callback> callbacks;
-#if HAVE_SIGACTION
+#ifndef SIGNAL_POLLING_UNSUPPORTED
     struct sigaction old_action;
 #endif
     bool was_blocked : 1;