2.2.5 Overriding Default Configuration Setting with config.site

When installing several packages using the same setup, it can be convenient to create a file to capture common settings. If a file named prefix/share/config.site exists, configure will source it at the beginning of its execution.

Recall the command from the previous section:

~/amhello-1.0 % ./configure --prefix ~/usr CC=gcc-3 \
CPPFLAGS=-I$HOME/usr/include LDFLAGS=-L$HOME/usr/lib

Assuming we are installing many package in ~/usr, and will always want to use these definitions of CC, CPPFLAGS, and LDFLAGS, we can automate this by creating the following ~/usr/share/config.site file:

test -z "$CC" && CC=gcc-3
test -z "$CPPFLAGS" && CPPFLAGS=-I$HOME/usr/include
test -z "$LDFLAGS" && LDFLAGS=-L$HOME/usr/lib

Now, any time a configure script is using the ~/usr prefix, it will execute the above config.site and define these three variables.

~/amhello-1.0 % ./configure --prefix ~/usr
configure: loading site script /home/adl/usr/share/config.site
…

See Setting Site Defaults in The Autoconf Manual, for more information about this feature.