4.12 Default Prefix

By default, configure sets the prefix for files it installs to `/usr/local'. The user of configure can select a different prefix using the `--prefix' and `--exec-prefix' options. There are two ways to change the default: when creating configure, and when running it.

Some software packages might want to install in a directory other than `/usr/local' by default. To accomplish that, use the AC_PREFIX_DEFAULT macro.

Macro: AC_PREFIX_DEFAULT (prefix)

Set the default installation prefix to prefix instead of `/usr/local'.

It may be convenient for users to have configure guess the installation prefix from the location of a related program that they have already installed. If you wish to do that, you can call AC_PREFIX_PROGRAM.

Macro: AC_PREFIX_PROGRAM (program)

If the user did not specify an installation prefix (using the `--prefix' option), guess a value for it by looking for program in PATH, the way the shell does. If program is found, set the prefix to the parent of the directory containing program, else default the prefix as described above (`/usr/local' or AC_PREFIX_DEFAULT). For example, if program is gcc and the PATH contains `/usr/local/gnu/bin/gcc', set the prefix to `/usr/local/gnu'.