Automake generates support for the DESTDIR variable in all
install rules. DESTDIR is used during the ‘make install’
step to relocate install objects into a staging area. Each object and
path is prefixed with the value of DESTDIR before being copied
into the install area. Here is an example of typical DESTDIR usage:
mkdir /tmp/staging && make DESTDIR=/tmp/staging install
The mkdir command avoids a security problem if the attacker
creates a symbolic link from /tmp/staging to a victim area;
then make places install objects in a directory tree built under
/tmp/staging. If /gnu/bin/foo and
/gnu/share/aclocal/foo.m4 are to be installed, the above command
would install /tmp/staging/gnu/bin/foo and
/tmp/staging/gnu/share/aclocal/foo.m4.
This feature is commonly used to build install images and packages (see Building Binary Packages Using DESTDIR).
Support for DESTDIR is implemented by coding it directly into
the install rules. If your Makefile.am uses a local install
rule (e.g., install-exec-local) or an install hook, then you
must write that code to respect DESTDIR.
See Makefile Conventions in The GNU Coding Standards, for another usage example.