Do not use undefined preprocessor macros. (#186)

mcourteaux · web-flow · commit e379d5f05866 · 2025-05-02T12:08:29.000-06:00
This fixes a warning produced when using `-Wundef`.
diff --git a/include/foonathan/memory/config.hpp b/include/foonathan/memory/config.hpp
@@ -35,7 +35,7 @@
 
 // hosted implementation
 #ifndef FOONATHAN_HOSTED_IMPLEMENTATION
-#if !_MSC_VER && !__STDC_HOSTED__
+#if !defined(_MSC_VER) && !defined(__STDC_HOSTED__)
 #define FOONATHAN_HOSTED_IMPLEMENTATION 0
 #else
 #define FOONATHAN_HOSTED_IMPLEMENTATION 1
