Script might well override a static map, but can't risk it not doing it, and preview completely failing. Better to just not try it for static maps. Some script cfg might help. Could also avoid unnnecessary preview regenerations even if the script was doing nothing at all.
# Find GLEW
#
# Once done this will define
# GLEW_FOUND - system has GLEW
# GLEW_INCLUDE_DIR - the GLEW include directory
# GLEW_LIBRARY - The library needed to use GLEW
# Copyright (c) 2013, Vittorio Giovara <vittorio.giovara@gmail.com>
#
# Distributed under the OSI-approved BSD License (the "License");
# see accompanying file Copyright.txt for details.
#
# This software is distributed WITHOUT ANY WARRANTY; without even the
# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
# See the License for more information.
include(FindPackageHandleStandardArgs)
find_path( GLEW_INCLUDE_DIR GL/glew.h
/usr/include
/usr/local/include
/sw/include
/opt/local/include
$ENV{PROGRAMFILES}/GLEW/include
DOC "The directory where GL/glew.h resides")
find_library( GLEW_LIBRARY
NAMES GLEW glew glew32 glew32s
PATHS
/usr/lib64
/usr/lib
/usr/local/lib64
/usr/local/lib
/sw/lib
/opt/local/lib
$ENV{PROGRAMFILES}/GLEW/lib
DOC "The GLEW library")
find_package_handle_standard_args(GLEW DEFAULT_MSG GLEW_LIBRARY GLEW_INCLUDE_DIR)
mark_as_advanced(GLEW_LIBRARY GLEW_INCLUDE_DIR)