Patch to make openbsc find libsmpp34

This patch lets the build script for openbsc find the libsmpp34 installation
with the help of pkg-config instead of assuming the header files are in
/usr/include.
diff --git a/openbsc/src/libmsc/Makefile.am b/openbsc/src/libmsc/Makefile.am
index 18bfa0c..5195890 100644
--- a/openbsc/src/libmsc/Makefile.am
+++ b/openbsc/src/libmsc/Makefile.am
@@ -1,6 +1,6 @@
 AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include -I$(top_builddir)
 AM_CFLAGS=-Wall $(LIBOSMOCORE_CFLAGS) $(LIBOSMOVTY_CFLAGS) \
-	$(LIBOSMOABIS_CFLAGS) $(COVERAGE_CFLAGS) $(LIBCRYPTO_CFLAGS)
+	$(LIBOSMOABIS_CFLAGS) $(COVERAGE_CFLAGS) $(LIBCRYPTO_CFLAGS) $(LIBSMPP34_CFLAGS)
 
 noinst_HEADERS = meas_feed.h