meta-toolchain-sysmobts: Introduce a toolchain target for the BTS

Install the sysmobts firmware headers on top of the Osmocom toolchain.
This way the SDK can be used to re-compile both the OpenBSC and the
osmo-bts software.

Make sure the -dev package of the femtobts-api has not runtime
dependencies to a library that does not exist.

recipes-bsp/meta/meta-toolchain-sysmobts.bb

@@ -0,0 +1,9 @@
+# Depend on the osmocom toolchain
+require recipes-osmocom/meta/meta-toolchain-osmo.bb
+
+# Change the name
+TOOLCHAIN_OUTPUTNAME = "${SDK_NAME}-toolchain-sysmobts-${DISTRO_VERSION}-${DATETIME}"
+
+# Add API headers..
+TOOLCHAIN_TARGET_TASK += "femtobts-api-dev"
+

recipes-sysmobts/femtobts-api/femtobts-api_git.bb

@@ -7,9 +7,12 @@ SRCREV = "6eb9bcf22ca5163594d4d0d8ec7dd580d411d1ea"
 SRCREV_sysmobts-v2 = "6eb9bcf22ca5163594d4d0d8ec7dd580d411d1ea"
 SRCREV_sysmobts-v1 = "4dde9443e2aa11868e46a67529cb5ac45462699c"
 PV = "${SRCREV}+git${SRCPV}"
-PR = "r2"
+PR = "r3"
 S = "${WORKDIR}/git"
 
+# The API is only a header, nothing to compile
+RDEPENDS_${PN}-dev = ""
+
 
 do_compile() {
 	: