+@subsubheading Overriding @command{configure} test results
+
+Sometimes, it might be necessary to override the result of some
+@command{configure} test, for example in order to ease porting to a new
+system or work around a bug in a test. The toplevel @command{configure}
+script provides three variables for this:
+
+@table @code
+
+@item build_configargs
+@cindex @code{build_configargs}
+The contents of this variable is passed to all build @command{configure}
+scripts.
+
+@item host_configargs
+@cindex @code{host_configargs}
+The contents of this variable is passed to all host @command{configure}
+scripts.
+
+@item target_configargs
+@cindex @code{target_configargs}
+The contents of this variable is passed to all target @command{configure}
+scripts.
+
+@end table
+
+In order to avoid shell and @command{make} quoting issues for complex
+overrides, you can pass a setting for @env{CONFIG_SITE} and set
+variables in the site file.
+