diff --git a/loader/Makefile.in b/loader/Makefile.in
index 8f4d2a262c5..59111592e3b 100644
--- a/loader/Makefile.in
+++ b/loader/Makefile.in
@@ -2,6 +2,7 @@ TOPSRCDIR = @top_srcdir@
 TOPOBJDIR = ..
 SRCDIR    = @srcdir@
 VPATH     = @srcdir@
+DEFS      = -D__WINESRC__ $(EXTRADEFS)
 
 C_SRCS = \
 	main.c \