[CMake] using component install still installs all files

[Rosen Diankov]

hi all,

we're making a debian source package which requires the cmake command to be:

cmake -DCMAKE_INSTALL_PREFIX=/usr .

in order to get the individual component files installed we do:

cmake -DCOMPONENT=MYCOMP -DCMAKE_INSTALL_PREFIX=tempdir -P cmake_install.cmake
make install

although this installs all MYCOMP files in tempdir, it also installs
all files into /usr

How can we tell cmake to ignore installing into /usr? In order to get
the linking correct, we need to set /usr, but that doesn't have write
permissions, so things fail.

thank you,
rosen diankov,