use system-wide libtalloc with --enable-system-talloc
This introduces a new configure flag by which the libosmocore-internal
talloc code is not compiled, but rather a system-wide libtalloc is used.
When we started openbsc/libosmocore in 2008, libtalloc was not widely
present on systems yet. This has changed meanwhile, and we should
simply use the system-wide library
diff --git a/libosmocore.pc.in b/libosmocore.pc.in
index 7c29869..0666e0c 100644
--- a/libosmocore.pc.in
+++ b/libosmocore.pc.in
@@ -6,6 +6,6 @@
Name: Osmocom Core Library
Description: C Utility Library
Version: @VERSION@
-Libs: -L${libdir} -losmocore
+Libs: -L${libdir} @TALLOC_LIBS@ -losmocore
Cflags: -I${includedir}/