Allow building shared or static library only
Allow building shared or static library only

Patchs retrieved from:
 - https://git.buildroot.net/buildroot/tree/package/zmqpp/0001-Allow-building-shared-or-static-library-only.patch
 - https://git.buildroot.net/buildroot/tree/package/zmqpp/0002-Install-static-library-for-static-builds.patch

Both patches have been merged in a single one and slightly updated to
keep default behavior of building and installing static library
(BUILD_STATIC is set to yes by default)

Signed-off-by: Jörg Krause <a3c6a141b7ae4e670c91aa105ccadae5e33bda16@embedded.rocks>
Signed-off-by: Gustavo Zacarias <beac5f8171fcde5e2ec734cc5d25d03e7362e8de@zacarias.com.ar>
Signed-off-by: Fabrice Fontaine <7d88633730b8b85c1516e612893df72eae9cd341@gmail.com>

zeromq/zmqpp,zeromq/zmqpp