diff --git a/mozilla/xpcom/src/Makefile.in b/mozilla/xpcom/src/Makefile.in
index db6daa64dd5..bb3858bc8dd 100644
--- a/mozilla/xpcom/src/Makefile.in
+++ b/mozilla/xpcom/src/Makefile.in
@@ -41,6 +41,7 @@ CPPSRCS		= \
 	nsTraceRefcnt.cpp \
 	nsProxyEvent.cpp \
 	nsXPComFactory.cpp \
+	nsXPIDLString.cpp \
 	nsEventQueueService.cpp \
 	xcDll.cpp \
 	xcDllStore.cpp \
diff --git a/mozilla/xpcom/src/makefile.win b/mozilla/xpcom/src/makefile.win
index 44acae37b8a..bbf8b92ae93 100644
--- a/mozilla/xpcom/src/makefile.win
+++ b/mozilla/xpcom/src/makefile.win
@@ -66,6 +66,7 @@ CPPSRCS =                             \
         nsTraceRefcnt.cpp             \
         nsRegistry.cpp                \
         nsXPComFactory.cpp            \
+        nsXPIDLString.cpp             \
         nsEventQueueService.cpp       \
         nsAllocator.cpp               \
         xcDll.cpp                     \