Link -ldl with tests only

configure.ac

@@ -69,9 +69,15 @@ AM_CONDITIONAL([HAVE_STDCXX_11],
 
 # Checks for libraries.
 
+# Additional libraries required for tests.
+TESTS_LIBS=
+
+LIBS_OLD=$LIBS
 # Search for dlsym function, which is used in tests. Linux needs -ldl,
 # but netbsd does not need it.
 AC_SEARCH_LIBS([dlsym], [dl])
+TESTS_LIBS=$LIBS $TESTS_LIBS
+LIBS=$LIBS_OLD
 
 # zlib
 PKG_CHECK_MODULES([ZLIB], [zlib >= 1.2.3])
@@ -235,6 +241,8 @@ if test "x$maintainer_mode" != "xno"; then
     CFLAGS="$CFLAGS -Wno-unused-parameter"
 fi
 
+AC_SUBST([TESTS_LIBS])
+
 AC_CONFIG_FILES([
   Makefile
   lib/Makefile

tests/Makefile.am

@@ -41,7 +41,7 @@ HFILES = spdylay_pq_test.h spdylay_map_test.h spdylay_queue_test.h \
 main_SOURCES = $(HFILES) $(OBJECTS)
 
 main_LDADD = ${top_builddir}/lib/libspdylay.la
-main_LDFLAGS = -static @CUNIT_LIBS@
+main_LDFLAGS = -static @CUNIT_LIBS@ @TESTS_LIBS@
 
 failmalloc_SOURCES = failmalloc.c failmalloc_test.c failmalloc_test.h \
 	malloc_wrapper.c malloc_wrapper.h \