Get rid of the libgcrypt explicit dependency Libotr depends on libgcrypt, but mcabber itself does not, so we don't have to check for it in the configure script. (Reported by Ryan Schmidt.)

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