diff --git a/src/support/strfwd.h b/src/support/strfwd.h
index de8588cabc..e40ec1c4b8 100644
--- a/src/support/strfwd.h
+++ b/src/support/strfwd.h
@@ -17,7 +17,7 @@
 // if libc++ is used (rather than libstdc++) - we first
 // check if we have at least a c++03 standard before
 // including the file
-#if (__cplusplus > 19971L)
+#if (__cplusplus > 199711L)
 #include <ciso646>
 #endif
 
diff --git a/src/tex2lyx/Parser.h b/src/tex2lyx/Parser.h
index 57a5cb1bf8..9778765ed6 100644
--- a/src/tex2lyx/Parser.h
+++ b/src/tex2lyx/Parser.h
@@ -125,7 +125,7 @@ public:
 
 	iparserdocstream(idocstream & is) : is_(is) {}
 
-#if (__cplusplus > 19971L)
+#if (__cplusplus > 199711L)
 	/// Like std::istream::operator bool()
 	/// Do not convert is_ implicitly to bool, since that is forbidden in C++11.
 	explicit operator bool() const { return s_.empty() ? !is_.fail() : true; }