Fix for build on FreeBSD

[VVD]

freebsd-amd64.cmake:

# the name of the target operating system
set(CMAKE_SYSTEM_NAME FreeBSD)
set(CMAKE_SYSTEM_PROCESSOR amd64)

# which compilers to use for C and C++
set(CMAKE_C_COMPILER clang)
set(CMAKE_CXX_COMPILER clang++)

# adjust the default behaviour of the FIND_XXX() commands:
# search headers and libraries in the target environment, search
# programs in the host environment
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)

[VVD]

--- a/build_cmake.sh
+++ b/build_cmake.sh
@@ -1,4 +1,4 @@
-#!/bin/bash -e
+#!/usr/bin/env bash
 
 # Useful if you willing to stop on first error, also prints what is executed.
 #set -ex