/** @page env Environment variables
@section LIBQUVI_EXCLUSIVE_SCRIPTS_DIR
When defined, the library will *only* use those scripts found at the
directories specified by the LIBQUVI_SCRIPTS_DIR.
@note Useful, for example, when the current set of the scripts at
$top_srcdir/share/ (of libquvi-scripts) are being tested by the
testsuite of the libquvi-scripts. The library would, otherwise,
include the scripts from the libquvi-scripts instance built with
the library and likely interfere with the tests.
@section LIBQUVI_SCRIPTS_DIR
When defined, the library will additionally look in the colon-separated list of
directories specified by the LIBQUVI_SCRIPTS_DIR environment variable.
@section LIBQUVI_SHOW_DIR
When defined, the library will output the paths of the searched directories to
the stderr.
@section LIBQUVI_SHOW_SCRIPT
When defined, the library will output the file names of the found scripts to stderr.
The output will also indicate whether the script was accepted by the library.
@section LIBQUVI_SCRIPTS_VERBOSE
When defined, scripts using the 'quvi/debug' module messaging functions will output
to stderr.
@section Proxy
Refer to the libcurl C API, or curl(1), documentation for a complete list of the
supported environment variables. libquvi uses libcurl to access the Internet.
@sa http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTPROXY
*/