diff --git a/rosapps/applications/screensavers/blankscr/blankscr.rbuild b/rosapps/applications/screensavers/blankscr/blankscr.rbuild
index c6960894245..6b7ca7af67b 100644
--- a/rosapps/applications/screensavers/blankscr/blankscr.rbuild
+++ b/rosapps/applications/screensavers/blankscr/blankscr.rbuild
@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <!DOCTYPE module SYSTEM "../../../../tools/rbuild/project.dtd">
 <module name="blankscr" type="win32scr" installbase="system32" installname="scrnsave.scr" unicode="yes">
-	<importlibrary definition="scrnsave.def" />
+	<importlibrary definition="scrnsave.spec.def" />
 	<library>scrnsave</library>
 	<library>kernel32</library>
 	<library>user32</library>
@@ -9,4 +9,5 @@
 
 	<file>scrnsave.c</file>
 	<file>scrnsave.rc</file>
+	<file>scrnsave.spec</file>
 </module>
diff --git a/rosapps/applications/screensavers/blankscr/scrnsave.def b/rosapps/applications/screensavers/blankscr/scrnsave.def
deleted file mode 100644
index ff549fee676..00000000000
--- a/rosapps/applications/screensavers/blankscr/scrnsave.def
+++ /dev/null
@@ -1,5 +0,0 @@
-NAME	blankscr.SCR
-
-EXPORTS
-	ScreenSaverProc
-	ScreenSaverConfigureDialog
diff --git a/rosapps/applications/screensavers/blankscr/scrnsave.spec b/rosapps/applications/screensavers/blankscr/scrnsave.spec
new file mode 100644
index 00000000000..ac72010d393
--- /dev/null
+++ b/rosapps/applications/screensavers/blankscr/scrnsave.spec
@@ -0,0 +1,2 @@
+@ stdcall ScreenSaverProc(ptr long ptr ptr)
+@ stdcall ScreenSaverConfigureDialog(ptr long ptr ptr)
diff --git a/rosapps/applications/screensavers/butterflies/butterflies.def b/rosapps/applications/screensavers/butterflies/butterflies.def
deleted file mode 100644
index 0f37ad2e775..00000000000
--- a/rosapps/applications/screensavers/butterflies/butterflies.def
+++ /dev/null
@@ -1,10 +0,0 @@
-NAME	butterflies.SCR
-
-DESCRIPTION	'OpenGL Butterflies screen saver'
-
-HEAPSIZE 1024
-STACKSIZE 4096
-
-EXPORTS
-	ScreenSaverProc
-	ScreenSaverConfigureDialog
diff --git a/rosapps/applications/screensavers/butterflies/butterflies.rbuild b/rosapps/applications/screensavers/butterflies/butterflies.rbuild
index 8da00a1e968..19a55edf7fd 100644
--- a/rosapps/applications/screensavers/butterflies/butterflies.rbuild
+++ b/rosapps/applications/screensavers/butterflies/butterflies.rbuild
@@ -1,7 +1,7 @@
 <?xml version="1.0"?>
 <!DOCTYPE module SYSTEM "../../../../tools/rbuild/project.dtd">
 <module name="butterflies" type="win32scr" installbase="system32" installname="butterflies.scr" unicode="yes">
-	<importlibrary definition="butterflies.def" />
+	<importlibrary definition="butterflies.spec.def" />
 	<include base="butterflies">.</include>
 	<library>scrnsave</library>
 	<library>kernel32</library>
@@ -16,4 +16,5 @@
 
 	<file>butterflies.c</file>
 	<file>butterflies.rc</file>
+	<file>butterflies.spec</file>
 </module>
diff --git a/rosapps/applications/screensavers/butterflies/butterflies.spec b/rosapps/applications/screensavers/butterflies/butterflies.spec
new file mode 100644
index 00000000000..ac72010d393
--- /dev/null
+++ b/rosapps/applications/screensavers/butterflies/butterflies.spec
@@ -0,0 +1,2 @@
+@ stdcall ScreenSaverProc(ptr long ptr ptr)
+@ stdcall ScreenSaverConfigureDialog(ptr long ptr ptr)