configure: fix static link with openssl

Use pkg-config to find openssl libraries, that will return all the
dependent libraries of openssl as well (e.g. -lz) that can not be
deduced in case of a static link.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
configure: fix static link with alsa

Use pkg-config to find the alsa library, that will return all the
dependent libraries of alsa (e.g. -ldl -lpthread -lrt) as well that
can not be deduced in case of a static link.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
configure: fix static link with popt

Use pkg-config to find the popt library.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Merge pull request #18 from yann-morin-1998/yem/static-link

Fix static linking (branch yem/static-link)