--- Makefile.orig
+++ Makefile
@@ -1,7 +1,6 @@
-CC ?= gcc
-CFLAGS_BENCH ?= -std=gnu99 -O3
+CFLAGS_BENCH ?= -std=gnu99
 LFLAGS_BENCH ?= -lpng
-CFLAGS_CONV ?= -std=c99 -O3
+CFLAGS_CONV ?= -std=c99
 
 TARGET_BENCH ?= qoibench
 TARGET_CONV ?= qoiconv
@@ -11,11 +10,11 @@ all: $(TARGET_BENCH) $(TARGET_CONV)
 bench: $(TARGET_BENCH)
 
 $(TARGET_BENCH):$(TARGET_BENCH).c
-	$(CC) $(CFLAGS_BENCH) $(CFLAGS) $(TARGET_BENCH).c -o $(TARGET_BENCH) $(LFLAGS_BENCH)
+	$(CC) $(CFLAGS_BENCH) $(CFLAGS) -I@PREFIX@/include/stb $(TARGET_BENCH).c -o $(TARGET_BENCH) $(LFLAGS_BENCH)
 
 conv: $(TARGET_CONV)
 $(TARGET_CONV):$(TARGET_CONV).c
-	$(CC) $(CFLAGS_CONV) $(CFLAGS) $(TARGET_CONV).c -o $(TARGET_CONV)
+	$(CC) $(CFLAGS_CONV) $(CFLAGS) -I@PREFIX@/include/stb $(TARGET_CONV).c -o $(TARGET_CONV)
 
 .PHONY: clean
 clean: