package/gensio: add alsa-lib optional dependency

alsa-lib is an optional dependency which is enabled by default since
version 2.5.3 and
https://github.com/cminyard/gensio/commit/dc9bad87d47588dcdd92ce118fcc4f41d10b671c

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gensio/gensio.mk

@@ -14,6 +14,13 @@ GENSIO_CONF_OPTS = \
 	--without-swig \
 	--without-python
 
+ifeq ($(BR2_PACKAGE_ALSA_LIB_PCM),y)
+GENSIO_DEPENDENCIES += alsa-lib
+GENSIO_CONF_OPTS += --with-alsa
+else
+GENSIO_CONF_OPTS += --without-alsa
+endif
+
 ifeq ($(BR2_PACKAGE_LIBGLIB2),y)
 GENSIO_DEPENDENCIES += host-pkgconf libglib2
 GENSIO_CONF_OPTS += --with-glib