diff --git a/lib/asn1/NTMakefile b/lib/asn1/NTMakefile
index 84895900d..a2bbf229f 100644
--- a/lib/asn1/NTMakefile
+++ b/lib/asn1/NTMakefile
@@ -31,7 +31,7 @@
 
 RELDIR=lib\asn1
 
-intcflags=-I$(SRCDIR) -I$(OBJ) -DROKEN_RENAME -DASN1_IOS_SUPPORTED
+intcflags=-I$(SRCDIR) -I$(OBJ) -DROKEN_RENAME -DASN1_IOS_SUPPORTED -DASN1_LIB
 
 !include ../../windows/NTMakefile.w32