build: don't link libnm/libnm-core against libuuid

We use util-linux's libuuid for handling UUIDs. But UUIDs are
really a trivial thing, at least the portion that we use.

Reimplement the parse/unparse/generate_random() methods and drop
the dependency. Note that no other libraries from our dependency chain
was dragging in libuuid, so thereby we really get rid of the dependency.

We still require libuuid for building, because it is used by an example
program. Maybe that should be changed, to avoid the build dependency.
But that can be done at a later time.

Makefile.am

@@ -1394,7 +1394,6 @@ nodist_src_libnm_core_impl_libnm_core_impl_la_SOURCES = \
 
 src_libnm_core_impl_libnm_core_impl_la_LIBADD = \
 	$(GLIB_LIBS) \
-	$(UUID_LIBS) \
 	$(NULL)
 
 src_libnm_core_impl_libnm_core_impl_la_LDFLAGS = \
@@ -1762,7 +1761,6 @@ src_libnm_client_impl_libnm_client_impl_la_LIBADD = \
 	src/c-siphash/libc-siphash.la \
 	$(GLIB_LIBS) \
 	$(DL_LIBS) \
-	$(UUID_LIBS) \
 	$(LIBUDEV_LIBS) \
 	$(NULL)
 

src/libnm-core-impl/nm-utils.c

@@ -11,7 +11,6 @@
 #include <net/ethernet.h>
 #include <arpa/inet.h>
 #include <net/if_arp.h>
-#include <uuid/uuid.h>
 #include <libintl.h>
 #include <gmodule.h>
 #include <sys/stat.h>