Most notably, this allows to define OTHER_CPP to the empty string. Which
effectively speeds up the build by not creating a local.a, and disabling symbol
sharing in that directory by means of the library. With local.a, all other .so
files have to be relinked and installed to BUILD_LIB_DIR after a change in a
single source file.
Signed-off-by: Jan Lindemann <jan@janware.com>