+ /* Try to run a program as indicated by the argument list AV.
+ *
+ * This is essentially execvp(3). If `TEF_VERBOSE' is set in F then
+ * trace what's going on to standard error. If `TEF_DRYRUN' is set
+ * in F then don't actually try to run the program: just check
+ * whether it exists and is vaguely plausible. Return -1 if there
+ * was a problem, or 0 if it was successful but didn't actually run
+ * the program because of the flags settings.
+ */
+
+extern void init_config(void);
+ /* Initialize the configuration machinery.
+ *
+ * This establishes the standard configuration sections `@CONFIG',
+ * `@BUILTIN', `@COMMON', and `@ENV', setting the corresponding
+ * global variables, and populates `@BUILTIN' (from compile-time
+ * configuration) and `@ENV' (from the environment variables).
+ */