diff --git a/src/insets/InsetCommandParams.cpp b/src/insets/InsetCommandParams.cpp
index 23ddf13af5..eaf5b41dec 100644
--- a/src/insets/InsetCommandParams.cpp
+++ b/src/insets/InsetCommandParams.cpp
@@ -77,7 +77,7 @@ static ParamInfo const & findInfo(InsetCode code, string const & cmdName)
 	default:
 		LASSERT(false, /**/);
 	}
-	static const ParamInfo pi;
+	static ParamInfo pi;
 	return pi; // to silence the warning
 }
 
diff --git a/src/mathed/MathData.h b/src/mathed/MathData.h
index a848e83c0f..1134be1821 100644
--- a/src/mathed/MathData.h
+++ b/src/mathed/MathData.h
@@ -20,6 +20,7 @@
 
 #include "support/strfwd.h"
 
+#include <cstddef>
 #include <vector>
 
 
diff --git a/src/support/weighted_btree.h b/src/support/weighted_btree.h
index babb2258ce..b64f95366f 100644
--- a/src/support/weighted_btree.h
+++ b/src/support/weighted_btree.h
@@ -29,6 +29,7 @@
 // *** Required Headers from the STL
 
 #include <algorithm>
+#include <cstddef>
 #include <functional>
 #include <istream>
 #include <ostream>