Use LDFLAGS for tests, too

Upstream PR: https://github.com/wbhart/flint2/pull/209


--- a/Makefile.in	2016-01-09 01:44:52.178779543 +0100
+++ b/Makefile.in	2016-01-09 01:44:19.874183406 +0100
@@ -227,7 +227,7 @@
 	$(QUIET_CC) $(CC) $(CFLAGS) $(INCS) -c $< -o $@;
 
 build/test/%$(EXEEXT): test/%.c $(HEADERS) | build/test
-	$(QUIET_CC) $(CC) $(CFLAGS) $(INCS) $< -o $@ $(LIBS)
+	$(QUIET_CC) $(CC) $(CFLAGS) $(INCS) $(LDFLAGS) $< -o $@ $(LIBS)
 
 build/test:
 	mkdir -p build/test
@@ -242,7 +242,7 @@
 	$(QUIET_CXX) $(CXX) $(CXXFLAGS) $(INCS) -c $< -o $@
 
 build/interfaces/test/t-NTL-interface$(EXEEXT): interfaces/test/t-NTL-interface.cpp build/interfaces/NTL-interface.o
-	$(QUIET_CXX) $(CXX) $(CXXFLAGS) $(INCS) $< build/interfaces/NTL-interface.o -o $@ $(LIBS)
+	$(QUIET_CXX) $(CXX) $(CXXFLAGS) $(INCS) $(LDFLAGS) $< build/interfaces/NTL-interface.o -o $@ $(LIBS)
 
 print-%:
 	@echo '$*=$($*)'
