diff --git a/Fltk/pluginWindow.cpp b/Fltk/pluginWindow.cpp
index 77a87681618e468e6e48df37babf3a305b4e60c9..c8bc3ccca97458d431e8a17a4749f13a03182a59 100644
--- a/Fltk/pluginWindow.cpp
+++ b/Fltk/pluginWindow.cpp
@@ -4,6 +4,7 @@
 // bugs and problems to <gmsh@geuz.org>.
 
 #include <vector>
+#include <string.h>
 #include <FL/Fl_Return_Button.H>
 #include <FL/Fl_Group.H>
 #include <FL/Fl_Value_Input.H>
diff --git a/Fltk/projectionEditor.cpp b/Fltk/projectionEditor.cpp
index 68d3b8b99ad7d280983e4133f20dde67dc9a9ccb..b1bdfdc5196eba42f35fb8e1d03c6ec5b0b88d97 100644
--- a/Fltk/projectionEditor.cpp
+++ b/Fltk/projectionEditor.cpp
@@ -3,6 +3,7 @@
 // See the LICENSE.txt file for license information. Please report all
 // bugs and problems to <gmsh@geuz.org>.
 
+#include <string.h>
 #include <FL/fl_draw.H>
 #include <FL/Fl_Box.H>
 #include <FL/Fl_Scroll.H>