fix install-build-deps.sh to run on FreeBSD

scripts/install-build-deps.sh

@@ -1,7 +1,10 @@
-#!/bin/bash -eu
+#!/usr/bin/env bash
 #
 # Install build dpenedencies.
 
+set -e
+set -u
+
 platform=$(uname -s)
 
 if [ -e /etc/os-release ]; then
@@ -23,6 +26,9 @@ case $platform in
 		yum install -y \
 			gcc make cmake zlib-devel openssl-devel rpm-build
 		;;
+	FreeBSD-freebsd)
+		pkg install cmake
+		;;
 	*)
 		echo "unsupported platform: $platform"
 		exit 1