File: autoconf.info,  Node: Defining Variables,  Next: configure Invocation,  Prev: Sharing Defaults,  Up: Running configure Scripts

16.8 Defining Variables
=======================

Variables not defined in a site shell script can be set in the
environment passed to ‘configure’.  However, some packages may run
configure again during the build, and the customized values of these
variables may be lost.  In order to avoid this problem, you should set
them in the ‘configure’ command line, using ‘VAR=value’.  For example:

     ./configure CC=/usr/local2/bin/gcc

causes the specified ‘gcc’ to be used as the C compiler (unless it is
overridden in the site shell script).

Unfortunately, this technique does not work for ‘CONFIG_SHELL’ due to an
Autoconf limitation.  Until the limitation is lifted, you can use this
workaround:

     CONFIG_SHELL=/bin/bash ./configure CONFIG_SHELL=/bin/bash