[HWASAN] Add leak sanitizer flag support

[vitalybuka]

compiler-rt/lib/hwasan/hwasan.cpp

115

I remember detect_leaks = false in other patch

[vitalybuka]

rebase

compiler-rt/lib/hwasan/hwasan.cpp

#endif
 
   Flags *f = flags();
   f->SetDefaults();
 
   FlagParser parser;
   RegisterHwasanFlags(&parser, f);
   RegisterCommonFlags(&parser);
 
+#if CAN_SANITIZE_LEAKS
+  __lsan::Flags *lf = __lsan::flags();
+  lf->SetDefaults();
+
+  FlagParser lsan_parser;
+  __lsan::RegisterLsanFlags(&lsan_parser, lf);
+  RegisterCommonFlags(&lsan_parser);
+#endif
+
 #if HWASAN_CONTAINS_UBSAN
   __ubsan::Flags *uf = __ubsan::flags();
   uf->SetDefaults();
 
   FlagParser ubsan_parser;
   __ubsan::RegisterUbsanFlags(&ubsan_parser, uf);
   RegisterCommonFlags(&ubsan_parser);
 #endif
 
   // Override from user-specified string.
   if (__hwasan_default_options)
     parser.ParseString(__hwasan_default_options());
 #if HWASAN_CONTAINS_UBSAN
   const char *ubsan_default_options = __ubsan_default_options();
   ubsan_parser.ParseString(ubsan_default_options);
 #endif
 
   parser.ParseStringFromEnv("HWASAN_OPTIONS");
+#if CAN_SANITIZE_LEAKS
+  lsan_parser.ParseStringFromEnv("LSAN_OPTIONS");
+#endif
 #if HWASAN_CONTAINS_UBSAN
   ubsan_parser.ParseStringFromEnv("UBSAN_OPTIONS");
 #endif
 
   InitializeCommonFlags();
 
   if (Verbosity()) ReportUnrecognizedFlags();
 
   if (common_flags()->help) parser.PrintFlagDescriptions();
+  // Flag validation:
+  if (!CAN_SANITIZE_LEAKS && common_flags()->detect_leaks) {
+    Report("%s: detect_leaks is not supported on this platform.\n",
+           SanitizerToolName);
+    Die();
+  }
 }
 
 static void CheckUnwind() {
   GET_FATAL_STACK_TRACE_PC_BP(StackTrace::GetCurrentPc(), GET_CURRENT_FRAME());
   stack.Print();
 }
 
 static void HwasanFormatMemoryUsage(InternalScopedString &s) {