diff --git a/Makefile b/Makefile
index cd299f8506..a244b27ac6 100644
--- a/Makefile
+++ b/Makefile
@@ -7,7 +7,7 @@
 # BREAK YOUR LOCAL DIFFS! show-diff and anything using it will likely randomly
 # break unless your underlying filesystem supports those sub-second times
 # (my ext3 doesn't).
-CFLAGS=-g -O3 -Wall
+CFLAGS=-g -O2 -Wall
 
 CC=gcc
 AR=ar
diff --git a/cache.h b/cache.h
index eab355da5d..a67b79e97f 100644
--- a/cache.h
+++ b/cache.h
@@ -1,6 +1,7 @@
 #ifndef CACHE_H
 #define CACHE_H
 
+#include <unistd.h>
 #include <stdio.h>
 #include <sys/stat.h>
 #include <fcntl.h>