      DEC_INTERN_ASM_FIXIDX,
      DJGPP_WCHAR_H_FIXIDX,
      ECD_CURSOR_FIXIDX,
-@@ -10831,6 +10874,11 @@ tFixDesc fixDescList[ FIX_COUNT ] = {
+@@ -10739,6 +10778,11 @@
       DARWIN_STDINT_7_TEST_CT, FD_MACH_ONLY | FD_SUBROUTINE,
       aDarwin_Stdint_7Tests,   apzDarwin_Stdint_7Patch, 0 },
  

   {  zDec_Intern_AsmName,    zDec_Intern_AsmList,
      apzDec_Intern_AsmMachs,
      DEC_INTERN_ASM_TEST_CT, FD_MACH_ONLY,
diff --git a/fixincludes/inclhack.def b/fixincludes/inclhack.def
index 7f0fb9dc911..49ba499ecde 100644
--- a/fixincludes/inclhack.def
+++ b/fixincludes/inclhack.def
@@ -1635,6 +1635,25 @@ fix = {
 		"#define UINTMAX_C(v) (v ## ULL)";
 };
 
+/*  The SDK included with XCode 10.2 has the file <sys/ucred.h> that uses the
+    C11 _Atomic keyword (exposing it to C++ code).  The work-around here follows
+    the header in declaring the entity volatile when _Atomic is not available.
+*/
+fix = {
+    hackname  = darwin_ucred__Atomic;
+    mach      = "*-*-darwin*";
+    files     = sys/ucred.h;
+    select    = "_Atomic";
+    c_fix     = wrap;
+    c_fix_arg = "#if (__STDC_VERSION__ < 201112L) || defined(__cplusplus)\n"
+		"# define _Atomic volatile\n"
+		"#endif\n";
+    c_fix_arg = "#if (__STDC_VERSION__ < 201112L) || defined(__cplusplus)\n"
+		"# undef _Atomic\n"
+		"#endif\n";
+    test_text = "_Atomic";
+};
+

+ *  Machine/OS name selection pattern
+ */
+tSCC* apzDarwin_Ucred__AtomicMachs[] = {
+        "*-*-darwin18*",
+        (const char*)NULL };
+
+/*
