diff --git a/libs/canvas/constraint_test.cc b/libs/canvas/constraint_test.cc
index c5ac8fe349..cc62d14894 100644
--- a/libs/canvas/constraint_test.cc
+++ b/libs/canvas/constraint_test.cc
@@ -19,6 +19,10 @@ using namespace Gtk;
 using std::cerr;
 using std::endl;
 
+#ifdef PLATFORM_WINDOWS
+#define srandom() srand()
+#endif
+
 int
 main (int argc, char* argv[])
 {
diff --git a/libs/canvas/constraint_test2.cc b/libs/canvas/constraint_test2.cc
index 6bb10c2430..8070e70499 100644
--- a/libs/canvas/constraint_test2.cc
+++ b/libs/canvas/constraint_test2.cc
@@ -21,6 +21,10 @@ using namespace Gtk;
 using std::cerr;
 using std::endl;
 
+#ifdef PLATFORM_WINDOWS
+#define srandom() srand()
+#endif
+
 #define SQUARED 16
 
  struct Column {
diff --git a/libs/canvas/constraint_test3.cc b/libs/canvas/constraint_test3.cc
index 5fbb8bd9fb..5f38da3896 100644
--- a/libs/canvas/constraint_test3.cc
+++ b/libs/canvas/constraint_test3.cc
@@ -19,6 +19,10 @@ using namespace Gtk;
 using std::cerr;
 using std::endl;
 
+#ifdef PLATFORM_WINDOWS
+#define srandom() srand()
+#endif
+
 int
 main (int argc, char* argv[])
 {
diff --git a/libs/canvas/constraint_test4.cc b/libs/canvas/constraint_test4.cc
index a3f4e639c4..94982bc135 100644
--- a/libs/canvas/constraint_test4.cc
+++ b/libs/canvas/constraint_test4.cc
@@ -19,6 +19,10 @@ using namespace Gtk;
 using std::cerr;
 using std::endl;
 
+#ifdef PLATFORM_WINDOWS
+#define srandom() srand()
+#endif
+
 int
 main (int argc, char* argv[])
 {
diff --git a/libs/gtkmm2ext/colors.cc b/libs/gtkmm2ext/colors.cc
index 562c570b9a..0f9ded0ecd 100644
--- a/libs/gtkmm2ext/colors.cc
+++ b/libs/gtkmm2ext/colors.cc
@@ -23,6 +23,8 @@
 #include <cfloat>
 #include <cstdlib>
 
+#include <glib.h>
+
 #include "pbd/failed_constructor.h"
 #include "pbd/string_convert.h"
 
@@ -732,5 +734,5 @@ Gtkmm2ext::set_source_rgb_a (cairo_t *cr, Color color, float alpha)
 Color
 Gtkmm2ext::random_color ()
 {
-	return ((random() % 16777215) << 8 | 0xff);
+	return ((g_random_int() % 16777215) << 8 | 0xff);
 }