arrow

ARROW-7940: [C++] Remove ARROW_USE_CLCACHE handling

The recommended way to enable `clcache` is to pass the `CMAKE_CXX_COMPILER` option to CMake, or to set the `CXX` environment variable.

Closes #6508 from vvvy/ARROW-7940 and squashes the following commits:

ab9669922 <Antoine Pitrou> Remove obsolete ARROW_USE_CLCACHE option
66c308cc4 <Valery Vybornov> ARROW-7940:  Unable to generate cmake build with settings other than default

Lead-authored-by: Antoine Pitrou <antoine@python.org>
Co-authored-by: Valery Vybornov <vvybornov@gmail.com>
Signed-off-by: Antoine Pitrou <antoine@python.org>