diff --git a/mozilla/embedding/browser/gtk/tests/Makefile.in b/mozilla/embedding/browser/gtk/tests/Makefile.in
index 85e226281a3..a11a1e03c53 100644
--- a/mozilla/embedding/browser/gtk/tests/Makefile.in
+++ b/mozilla/embedding/browser/gtk/tests/Makefile.in
@@ -67,3 +67,14 @@ else
 CXXFLAGS        += $(MOZ_GTK_CFLAGS)
 
 endif
+
+ifeq ($(OS_ARCH), SunOS)
+ifndef GNU_CC
+# When using Sun's WorkShop compiler, including
+# /wherever/workshop-5.0/SC5.0/include/CC/std/time.h
+# causes most of these compiles to fail with:
+# line 29: Error: Multiple declaration for std::tm.
+# So, this gets around the problem.
+DEFINES           += -D_TIME_H=1
+endif
+endif