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

Makefile.am

@@ -49,7 +49,7 @@ bashcompletiondir = @bashcompletiondir@
 
 dist_noinst_HEADERS =
 noinst_PROGRAMS =
-noinst_LTLIBRARIES =
+EXTRA_LTLIBRARIES =
 usrbin_exec_PROGRAMS =
 usrsbin_exec_PROGRAMS =
 dist_man_MANS =

lib/Makemodule.am

@@ -9,7 +9,7 @@
 # Note that you need "make install-strip" (or proper rpm / Debian build)
 # to generate binaries with only relevant stuff.
 #
-noinst_LTLIBRARIES += libcommon.la
+EXTRA_LTLIBRARIES += libcommon.la
 libcommon_la_CFLAGS = $(AM_CFLAGS)
 libcommon_la_SOURCES = \
 	lib/blkdev.c \
@@ -60,7 +60,7 @@ libcommon_la_SOURCES += lib/sysfs.c
 endif
 endif
 
-noinst_LTLIBRARIES += libtcolors.la
+EXTRA_LTLIBRARIES += libtcolors.la
 libtcolors_la_CFLAGS = $(AM_CFLAGS)
 libtcolors_la_SOURCES = lib/colors.c lib/color-names.c include/colors.h include/color-names.h
 libtcolors_la_LIBADD =