diff --git a/cryptest.nmake b/cryptest.nmake
index 1a39a2c8..0da80cc7 100644
--- a/cryptest.nmake
+++ b/cryptest.nmake
@@ -237,6 +237,7 @@ cryptopp.dump: cryptlib.lib
 cryptopp.map:
 	$(LD) $(LDFLAGS) /DLL /MAP /MAPINFO:EXPORTS $(LIB_OBJS)
 	mv cryptlib.map cryptopp.map
+	get-content somefile.txt | %{$_ -replace "cryptlib","cryptopp"}
 
 cryptopp.def: cryptopp.dump
 	dump2def.exe cryptopp.dump cryptopp.def
diff --git a/tweetnacl.cpp b/tweetnacl.cpp
index aec6210e..466dc1e7 100644
--- a/tweetnacl.cpp
+++ b/tweetnacl.cpp
@@ -884,7 +884,7 @@ int crypto_sign_open(byte *m,word64 *mlen,const byte *sm,word64 n,const byte *pk
   byte t[32],h[64];
   gf p[4],q[4];
 
-  *mlen = -1;
+  *mlen = ~static_cast<word64>(0);
   if (n < 64) return -1;
 
   if (unpackneg(q,pk)) return -1;