[lldb] [FreeBSD] Fix building on systems without PT_COREDUMP

[mgorny]

Summary

PT_COREDUMP is a relatively recent addition. Use an #ifdef to skip it
if the underlying system does not support it.

lldb/source/Plugins/Process/FreeBSD/NativeProcessFreeBSD.cpp

NativeProcessFreeBSD::Factory::Attach(
   if (!status.Success())
     return status.ToError();
 
   return std::move(process_up);
 }
 
 NativeProcessFreeBSD::Extension
 NativeProcessFreeBSD::Factory::GetSupportedExtensions() const {
-  return Extension::multiprocess | Extension::fork | Extension::vfork |
-         Extension::pass_signals | Extension::auxv | Extension::libraries_svr4 |
-         Extension::savecore;
+  return
+#if defined(PT_COREDUMP)
+      Extension::savecore |
+#endif
+      Extension::multiprocess | Extension::fork | Extension::vfork |
+      Extension::pass_signals | Extension::auxv | Extension::libraries_svr4;
 }
 
 // Public Instance Methods
 
 NativeProcessFreeBSD::NativeProcessFreeBSD(::pid_t pid, int terminal_fd,
                                            NativeDelegate &delegate,
                                            const ArchSpec &arch,
                                            MainLoop &mainloop)
if (pt_error.Fail()) {
                      "unable to resume parent process {1}: {0}", GetID());
       SetState(StateType::eStateInvalid);
     }
   }
 }
 
 llvm::Expected<std::string>
 NativeProcessFreeBSD::SaveCore(llvm::StringRef path_hint) {
+#if defined(PT_COREDUMP)
   using namespace llvm::sys::fs;
 
   llvm::SmallString<128> path{path_hint};
   Status error;
   struct ptrace_coredump pc = {};
 
   // Try with the suggested path first.  If there is no suggested path or it
   // failed to open, use a temporary file.
   if (path.empty() ||
       openFile(path, pc.pc_fd, CD_CreateNew, FA_Write, OF_None)) {
     if (std::error_code errc =
             createTemporaryFile("lldb", "core", pc.pc_fd, path))
       return llvm::createStringError(errc, "Unable to create a temporary file");
   }
   error = PtraceWrapper(PT_COREDUMP, GetID(), &pc, sizeof(pc));
 
   std::error_code close_err = closeFile(pc.pc_fd);
   if (error.Fail())
     return error.ToError();
   if (close_err)
     return llvm::createStringError(
         close_err, "Unable to close the core dump after writing");
   return path.str().str();
+#else // !defined(PT_COREDUMP)
+  return llvm::createStringError(
+      llvm::inconvertibleErrorCode(),
+      "PT_COREDUMP not supported in the FreeBSD version used to build LLDB");
+#endif
 }

lldb/test/API/tools/lldb-server/TestGdbRemoteSaveCore.py

class TestGdbSaveCore(gdbremote_testcase.GdbRemoteTestCaseBase):
     mydir = TestBase.compute_mydir(__file__)
 
     def coredump_test(self, core_path=None, expect_path=None):
         self.build()
         self.set_inferior_startup_attach()
         procs = self.prep_debug_monitor_and_inferior()
         self.add_qSupported_packets()
         ret = self.expect_gdbremote_sequence()
-        self.assertIn("qSaveCore+", ret["qSupported_response"])
+        if "qSaveCore+" not in ret["qSupported_response"]:
+            self.skipTest("qSaveCore not supported by lldb-server")
         self.reset_test_sequence()
 
         packet = "$qSaveCore"
         if core_path is not None:
             packet += ";path-hint:{}".format(
                 binascii.b2a_hex(core_path.encode()).decode())
 
         self.test_sequence.add_log_lines([