diff --git a/include/boost/config/compiler/borland.hpp b/include/boost/config/compiler/borland.hpp
index 326906a7..e9bd981d 100644
--- a/include/boost/config/compiler/borland.hpp
+++ b/include/boost/config/compiler/borland.hpp
@@ -97,6 +97,10 @@
 //
 #define BOOST_HAS_DIRENT_H
 //
+// all versions support __declspec:
+//
+#define BOOST_HAS_DECLSPEC
+//
 // ABI fixing headers:
 //
 #ifndef BOOST_ABI_PREFIX
diff --git a/include/boost/config/compiler/visualc.hpp b/include/boost/config/compiler/visualc.hpp
index d70c5700..730896b5 100644
--- a/include/boost/config/compiler/visualc.hpp
+++ b/include/boost/config/compiler/visualc.hpp
@@ -89,6 +89,10 @@
 #  define BOOST_DISABLE_WIN32
 #endif
 
+//
+// all versions support __declspec:
+//
+#define BOOST_HAS_DECLSPEC
 //
 // prefix and suffix headers:
 //