Automake: use EXTRA_LTLIBRARIES instead of noinst_LTLIBRARIES

Automake: use EXTRA_LTLIBRARIES instead of noinst_LTLIBRARIES

noinst_LTLIBRARIES causes the libraries to be always built
unconditionally. EXTRA_LTLIBRARIES causes them to be built
only if other build target needs them.
In other words, avoid building libcommon.a and libtcolors.a
unless they are needed by another library/executable and
save some build time.

https://www.gnu.org/software/automake/manual/html_node/Libtool-Convenience-Libraries.html