diff --git a/toolkit/xre/Makefile.in b/toolkit/xre/Makefile.in
index 036321e37d2..113fcdf027f 100644
--- a/toolkit/xre/Makefile.in
+++ b/toolkit/xre/Makefile.in
@@ -117,7 +117,7 @@ SHAREDCMMSRCS += nsNativeAppSupportForCocoa.mm
 endif
 
 ifeq ($(MOZ_WIDGET_TOOLKIT),photon)
-SHAREDSRCS += nsNativeAppSupportPh.cpp
+SHAREDCPPSRCS += nsNativeAppSupportPh.cpp
 endif
 
 CPPSRCS = \