Don't hardcode optimization flags.
Add OpenBSD to supported OS list.

Index: configure
--- configure.orig
+++ configure
@@ -274,7 +274,7 @@ if test -z "$CFLAGS";then
 	if test "$cf_debug" = yes;then
 		CFLAGS_ADD=`fc_add_string "$CFLAGS_ADD" "-g -Wall"`
 	else
-		CFLAGS_ADD=`fc_add_string "$CFLAGS_ADD" "-O2 -Wall"`
+		CFLAGS_ADD=`fc_add_string "$CFLAGS_ADD" "-Wall"`
 	fi
 fi
 
@@ -290,6 +290,11 @@ elif test "$tmp1" = Darwin;then
 	CFLAGS=`fc_add_string "$CFLAGS" "-DMLK_NO_SIMD"`
 elif test "$tmp1" = FreeBSD;then
 	cf_os=freebsd
+	cf_make=gmake
+	CFLAGS=`fc_add_string "$CFLAGS" "-I/usr/local/include"`
+	LDFLAGS=`fc_add_string "$LDFLAGS" "-L/usr/local/lib"`
+elif test "$tmp1" = OpenBSD;then
+	cf_os=openbsd
 	cf_make=gmake
 	CFLAGS=`fc_add_string "$CFLAGS" "-I/usr/local/include"`
 	LDFLAGS=`fc_add_string "$LDFLAGS" "-L/usr/local/lib"`
