[libc++abi] NFC: Simplify extern C declaration

It seems to me that abort_message.h is always included in a C++ file, so
it's fine to assume that it's C++ code.

Differential Revision: https://reviews.llvm.org/D76027

diff --git a/libcxxabi/src/abort_message.h b/libcxxabi/src/abort_message.h
index 7cb11f4..83f956f 100644 (file)
--- a/libcxxabi/src/abort_message.h
+++ b/libcxxabi/src/abort_message.h
@@ -11,16 +11,7 @@
 
 #include "cxxabi.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-_LIBCXXABI_HIDDEN _LIBCXXABI_NORETURN void
+extern "C" _LIBCXXABI_HIDDEN _LIBCXXABI_NORETURN void
 abort_message(const char *format, ...) __attribute__((format(printf, 1, 2)));
 
-#ifdef __cplusplus
-}
 #endif
-
-#endif
-