remove our internal copy of talloc, use system libtalloc

Shipping our own private copy of talloc was a good idea in 2008,
when it was not readily available on most target platforms.  Today,
the situation is quite different, as it is a standard library on
major Linux distributions.
diff --git a/src/ctrl/Makefile.am b/src/ctrl/Makefile.am
index 71eced5..e6ccafb 100644
--- a/src/ctrl/Makefile.am
+++ b/src/ctrl/Makefile.am
@@ -2,13 +2,13 @@
 # Please read Chapter 6 "Library interface versions" of the libtool documentation before making any modification
 LIBVERSION=0:0:0
 
-AM_CFLAGS = -Wall $(all_includes) -I$(top_srcdir)/include -I$(top_builddir)/include
+AM_CFLAGS = -Wall $(all_includes) -I$(top_srcdir)/include -I$(top_builddir)/include $(TALLOC_CFLAGS)
 
 lib_LTLIBRARIES = libosmoctrl.la
 
 libosmoctrl_la_SOURCES = control_cmd.c control_if.c
 
-libosmoctrl_la_LDFLAGS = $(LTLDFLAGS_OSMOCTRL) -version-info $(LIBVERSION) -no-undefined
+libosmoctrl_la_LDFLAGS = $(LTLDFLAGS_OSMOCTRL) $(TALLOC_LIBS) -version-info $(LIBVERSION) -no-undefined
 libosmoctrl_la_LIBADD = \
 	$(top_builddir)/src/libosmocore.la \
 	$(top_builddir)/src/gsm/libosmogsm.la \