diff --git a/js/ctypes/Makefile.in b/js/ctypes/Makefile.in
--- a/js/ctypes/Makefile.in
+++ b/js/ctypes/Makefile.in
@@ -99,9 +99,15 @@
     -Ilibffi/include \
     $(NULL)
 
+ifndef XP_OS2
 SHARED_LIBRARY_LIBS = \
     libffi/.libs/$(LIB_PREFIX)ffi.$(LIB_SUFFIX) \
     $(NULL)
+else
+SHARED_LIBRARY_LIBS= \
+    libffi/.libs/$(LIB_PREFIX)ffi.a \
+    $(NULL)
+endif
 
 endif # _MSVC_VER