[libunwind] Clean up macro usage.

Convention in libunwind is to use !defined(FOOT) not !FOO.

Differential Revision: https://reviews.llvm.org/D31078

llvm-svn: 299225
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 5808011bd9f9b61b93cfe82953e5a03852a86aae
diff --git a/src/Unwind_AppleExtras.cpp b/src/Unwind_AppleExtras.cpp
index 8015150..471059b 100644
--- a/src/Unwind_AppleExtras.cpp
+++ b/src/Unwind_AppleExtras.cpp
@@ -77,7 +77,7 @@
 #endif
 
 
-#if _LIBUNWIND_BUILD_ZERO_COST_APIS
+#if defined(_LIBUNWIND_BUILD_ZERO_COST_APIS)
 
 //
 // symbols in libSystem.dylib in 10.6 and later, but are in libgcc_s.dylib in
@@ -116,12 +116,12 @@
 NEVER_HERE(__deregister_frame_info)
 NEVER_HERE(__deregister_frame_info_bases)
 
-#endif // _LIBUNWIND_BUILD_ZERO_COST_APIS
+#endif // defined(_LIBUNWIND_BUILD_ZERO_COST_APIS)
 
 
 
 
-#if _LIBUNWIND_BUILD_SJLJ_APIS
+#if defined(_LIBUNWIND_BUILD_SJLJ_APIS)
 //
 // symbols in libSystem.dylib in iOS 5.0 and later, but are in libgcc_s.dylib in
 // earlier versions
@@ -141,7 +141,7 @@
 NOT_HERE_BEFORE_5_0(_Unwind_SjLj_Resume_or_Rethrow)
 NOT_HERE_BEFORE_5_0(_Unwind_SjLj_Unregister)
 
-#endif // _LIBUNWIND_BUILD_SJLJ_APIS
+#endif // defined(_LIBUNWIND_BUILD_SJLJ_APIS)
 
 
 namespace libunwind {
@@ -184,7 +184,7 @@
 }
 
 
-#if !defined(FOR_DYLD) && _LIBUNWIND_BUILD_SJLJ_APIS
+#if !defined(FOR_DYLD) && defined(_LIBUNWIND_BUILD_SJLJ_APIS)
 
 #ifndef _LIBUNWIND_HAS_NO_THREADS
   #include <System/pthread_machdep.h>