[libc][NFC] Add a death test API adaptation macro

[michaelrj]

Summary

Fuchsia's zxtest has a slightly different death test definition, and
this macro makes our death test API work on Fuchsia.

[sivachandra]

You need update all tests with EXPECT|ASSERT_DEATH.

[michaelrj]

update all of the EXPECT_DEATH calls

libc/test/src/fenv/enabled_exceptions_test.cpp

ASSERT_DEATH(
           ASSERT_EQ(__llvm_libc::feraiseexcept(others), 0);
           ASSERT_EQ(__llvm_libc::fetestexcept(others), others);
 
           // We don't check the return value when raising |e| as
           // feraiseexcept will not return when it raises an enabled
           // exception.
           __llvm_libc::feraiseexcept(e);
         },
-        SIGFPE);
+        WITH_SIGNAL(SIGFPE));
   }
 }

libc/utils/UnitTest/FuchsiaTest.h

 //===-- Header for setting up the Fuchsia tests -----------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_LIBC_UTILS_UNITTEST_FUCHSIATEST_H
 #define LLVM_LIBC_UTILS_UNITTEST_FUCHSIATEST_H
 
 #include <zxtest/zxtest.h>
 
+#define WITH_SIGNAL(X) #X
+
 #endif // LLVM_LIBC_UTILS_UNITTEST_FUCHSIATEST_H

libc/utils/UnitTest/LibcTest.h

#define ASSERT_THAT(MATCH, MATCHER)                                            \
   do {                                                                         \
     auto UNIQUE_VAR(__matcher) = (MATCHER);                                    \
     if (!this->testMatch(UNIQUE_VAR(__matcher).match((MATCH)),                 \
                          UNIQUE_VAR(__matcher), #MATCH, #MATCHER, __FILE__,    \
                          __LINE__))                                            \
       return;                                                                  \
   } while (0)
 
+#define WITH_SIGNAL(X) X
+
 #endif // LLVM_LIBC_UTILS_UNITTEST_LIBCTEST_H