[clang][rtsan] Add realtime_sanitizer to Features.def (#106650)

Allows us to introduce the scoped disabler in #106736

Author: cjappl

clang/include/clang/Basic/Features.def

@@ -54,6 +54,8 @@ FEATURE(memtag_globals,
 FEATURE(xray_instrument, LangOpts.XRayInstrument)
 FEATURE(undefined_behavior_sanitizer,
         LangOpts.Sanitize.hasOneOf(SanitizerKind::Undefined))
+FEATURE(realtime_sanitizer,
+        LangOpts.Sanitize.has(SanitizerKind::Realtime))
 FEATURE(coverage_sanitizer, LangOpts.SanitizeCoverage)
 FEATURE(assume_nonnull, true)
 FEATURE(attribute_analyzer_noreturn, true)

clang/test/Lexer/has_feature_realtime_sanitizer.cpp

@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -E -fsanitize=realtime %s -o - | FileCheck --check-prefix=CHECK-RTSAN %s
+// RUN: %clang_cc1 -E  %s -o - | FileCheck --check-prefix=CHECK-NO-RTSAN %s
+
+#if __has_feature(realtime_sanitizer)
+int RealtimeSanitizerEnabled();
+#else
+int RealtimeSanitizerDisabled();
+#endif
+
+// CHECK-RTSAN: RealtimeSanitizerEnabled
+
+// CHECK-NO-RTSAN: RealtimeSanitizerDisabled