build: don't enable 'color-tests' automake option explicitly It's enabled by default since commit 'v1.12.2-136-g2d5571e' (this change appeared in Automake 1.13). * configure.ac (AM_INIT_AUTOMAKE): Drop 'color-tests'. Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>