TODO

/**
 * TODO:
 * - Fix temp stream closing to keep hashtable valid
 * - Check if command exists and is executable before opening the pipe
 * - Check if the file is actually a directory (?)
 * - Get prep.command order from the suffix (scan EG(ini_directives)) ?
 * 
 * FIXME:
 * - Add tmpfile handle to PREP_G that gets cleared out on RSHUTDOWN
 *   - (to keep the file from auto-deleting, so scripts can introspect/debug)
 *
 * DONE:
 * - Add function to get the filename of the processed file
 *   - Add hashtable mapping original path to temp file
 * - Allow multiple prep.command INI registrations
 *   - result of one command feeds back into the same tempfile for the next
 *     (if there's > 1)
 * - Change prep.command to be a formattable string:
 *   - %s: source, %o: original
 *   - error out if %s is not found?
 * - Add optional module dependencies on APC, xdebug, xhprof, and whatever else screws
 *   with the compile_file()
 * - Handle shebang (only in CLI):
 *   - reset CG(start_lineno)
 *   - do cli_seek_file_begin logic again on processed results
 * - Add function to get the filename of the processed file
 *   - Add hashtable mapping original path to temp file
 * - Check exit status of preprocessor command:
 *   - If 255, capture error and raise as E_COMPILE_ERROR
 *   - If 1, use the original file
 * - Check if the file is actually a directory
 * - FIXED require script (absolute path) (resolve realpath)
 */