Index: Makefile
--- Makefile.orig
+++ Makefile
@@ -36,7 +36,7 @@ test_b95u16: b95u16.c test_b95u16.c b95u16.h
 
 # --- container: PAS1 framing + libzstd + vendored SHA-256 (+ autocol for flags&1 blocks) ---
 test_pas1: pas1.c sha256.c autocol.c test_pas1.c pas1.h sha256.h autocol.h
-	$(CC) $(CFLAGS) -o $@ pas1.c sha256.c autocol.c test_pas1.c $(ZSTD)
+	$(CC) $(CPPFLAGS) $(CFLAGS) -o $@ pas1.c sha256.c autocol.c test_pas1.c $(ZSTD)
 
 # --- transform: autocol decode, built with sanitizers (the decoder is the safety surface) ---
 test_autocol: autocol.c test_autocol.c autocol.h
