remsim-client: Port from local copy to libosmousb + libosmo-simtrace2

We originally imported a copy of [most of] the code of
simtrace2.git/host into this repository.  That was a quick hack to get
things going, but now that simtrace2.git is providing a shared library
of simtrace2 utility functions, let's migrate over to it.

At the same time, some functions (libusb_util) have been migrated to
libosmousb (a new library in libosmocore.git), so we must add that
as new dependency, too.

This performs the minimally required changes and is *not* a proper
port to the libosmousb osmocore select loop integration, whcih will
follow in a separate patch.

Change-Id: Idf5a861f4dacbec3c664f4ced6e03d8662c73112
Closes: OS#4298
Related: OS#4299
Depends: libosmocore.git I656a1a38cbb5b1f3a9145d2869d3b4d0adefcae3
diff --git a/configure.ac b/configure.ac
index 2fc603d..d041c1a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -39,6 +39,8 @@
 PKG_CHECK_MODULES(OSMOGSM, libosmogsm >= 0.11.0)
 PKG_CHECK_MODULES(OSMOABIS, libosmoabis)
 PKG_CHECK_MODULES(OSMOSIM, libosmosim)
+PKG_CHECK_MODULES(OSMOUSB, libosmousb)
+PKG_CHECK_MODULES(OSMOSIMTRACE2, libosmo-simtrace2)
 PKG_CHECK_MODULES(USB, libusb-1.0)
 
 AC_ARG_ENABLE([remsim-server],[AS_HELP_STRING([--disable-remsim-server], [Build osmo-remsim-server])],