Fix multiple declarations issue with COLOR_ATTRIB This fails compilation with GCC 10 or -fno-common in CFLAGS. Link: https://bugs.gentoo.org/707418

SUBDIRS = mcabber doc modules
ACLOCAL_AMFLAGS = -I macros
if INSTALL_HEADERS
pkgconfigdir = $(libdir)/pkgconfig
pkgconfig_DATA = mcabber.pc
endif