tests: use -no-install libtool flag to avoid ./lt-* scripts

This option should be used for any executables which are used only
for testing, or for generating other files and are consequently never
installed.  By specifying this option, we are telling Libtool that
the executable it links will only ever be executed from where it is
built in the build tree.  Libtool is usually able to considerably
speed up the link process for such executables.

Change-Id: I2ca675e93dc5b34bb08d3b841adc115e93558137
diff --git a/tests/gtp/Makefile.am b/tests/gtp/Makefile.am
index e49d824..ef69260 100644
--- a/tests/gtp/Makefile.am
+++ b/tests/gtp/Makefile.am
@@ -1,4 +1,5 @@
 AM_CFLAGS = -Wall -I$(top_srcdir)/include $(LIBOSMOCORE_CFLAGS)
+AM_LDFLAGS = -no-install
 
 EXTRA_DIST = \
 	gtpie_test.ok \
diff --git a/tests/lib/Makefile.am b/tests/lib/Makefile.am
index 8f0301c..e807281 100644
--- a/tests/lib/Makefile.am
+++ b/tests/lib/Makefile.am
@@ -1,4 +1,5 @@
 AM_CFLAGS = -Wall -I$(top_srcdir)/include $(LIBOSMOCORE_CFLAGS)
+AM_LDFLAGS = -no-install
 
 EXTRA_DIST = ippool_test.ok \
 	     ippool_test.err \