build: Add -no-undefined where missing

Signed-off-by: orbea <orbea@riseup.net>

test-tool/Makefile.am

@@ -2,6 +2,7 @@ AM_CPPFLAGS=-I. -I${srcdir}/../include \
 	"-D_U_=__attribute__((unused)) " \
 	"-D_R_(A,B)=__attribute__((format(printf,A,B)))"
 AM_CFLAGS=$(WARN_CFLAGS)
+AM_LDFLAGS=-no-undefined
 LIBS = ../lib/libiscsipriv.la
 
 EXTRA_DIST = README