Fix an unfortunate yet old typo that never got attention before r250507.
Should fix the xcode libc++ build.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@250508 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/src/stdexcept.cpp b/src/stdexcept.cpp
index 577376e..0a08bfe 100644
--- a/src/stdexcept.cpp
+++ b/src/stdexcept.cpp
@@ -14,7 +14,7 @@
#include "system_error"
/* For _LIBCPPABI_VERSION */
-#if defined(LIBCXX_BUILDING_LIBCXXABI) || defined(__APPLE_) || defined(LIBCXXRT)
+#if defined(LIBCXX_BUILDING_LIBCXXABI) || defined(__APPLE__) || defined(LIBCXXRT)
#include <cxxabi.h>
#endif