Imported Upstream version 5.0.0.42

Former-commit-id: fd56571888259555122d8a0f58c68838229cea2b

mcs/class/referencesource/System/regex/system/text/regularexpressions/Regex.cs

@@ -405,7 +405,7 @@ namespace System.Text.RegularExpressions {
         * This method is internal virtual so the jit does not inline it.
         */
         [
-#if FEATURE_MONO_CAS
+#if MONO_FEATURE_CAS
             HostProtection(MayLeakOnAbort=true),
 #endif
             MethodImplAttribute(MethodImplOptions.NoInlining)
@@ -1252,7 +1252,7 @@ namespace System.Text.RegularExpressions {
 #if !(SILVERLIGHT || FULL_AOT_RUNTIME)
         /// <devdoc>
         /// </devdoc>
-#if FEATURE_MONO_CAS
+#if MONO_FEATURE_CAS
         [HostProtection(MayLeakOnAbort=true)]
 #endif
         [ResourceExposure(ResourceScope.Machine)] // The AssemblyName is interesting.
@@ -1265,7 +1265,7 @@ namespace System.Text.RegularExpressions {
 
         /// <devdoc>
         /// </devdoc>
-#if FEATURE_MONO_CAS
+#if MONO_FEATURE_CAS
         [HostProtection(MayLeakOnAbort=true)]
 #endif
         [ResourceExposure(ResourceScope.Machine)] // The AssemblyName is interesting.
@@ -1275,7 +1275,7 @@ namespace System.Text.RegularExpressions {
             CompileToAssemblyInternal(regexinfos, assemblyname, attributes, null);
         }
 
-#if FEATURE_MONO_CAS
+#if MONO_FEATURE_CAS
         [HostProtection(MayLeakOnAbort=true)]
 #endif
         [ResourceExposure(ResourceScope.Machine)]
@@ -1408,12 +1408,16 @@ namespace System.Text.RegularExpressions {
         /// <devdoc>
         /// </devdoc>
         protected bool UseOptionC() {
-		/* Mono: Set to false until we investigate  https://bugzilla.xamarin.com/show_bug.cgi?id=25671 */
-	    return false;
 #if FULL_AOT_RUNTIME
             return false;
 #else
+
+#if MONO
+            /* Mono: Set to false until we investigate  https://bugzilla.xamarin.com/show_bug.cgi?id=25671 */
+            return false;
+#else
             return(roptions & RegexOptions.Compiled) != 0;
+#endif
 #endif
         }
 #endif