build: use LDADD/LIBADD

Rather than manipulate LDFLAGS directly, the correct
way to pass additional linked-to libraries is via
the LDADD and LIBADD variables for executables and
libraries respectively.  Convert all cases of -lfoo
to LDADD/LIBADD.

Change-Id: Id5fb8539b3fa875430f297de37ad0f3e4ecc3726
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/test/Makefile.am b/test/Makefile.am
index fb1895c..cb2ffb7 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -1,46 +1,46 @@
 if WANT_LIBSDBUSPLUS
 
 AM_CPPFLAGS = -I$(top_srcdir) $(GTEST_CPPFLAGS)
-gtest_ldflags = -lgtest -lgtest_main
+gtest_ldadd = -lgtest -lgtest_main
 check_PROGRAMS =
 
 TESTS = $(check_PROGRAMS)
 
 check_PROGRAMS += bus_list_names
 bus_list_names_SOURCES = bus/list_names.cpp
-bus_list_names_LDFLAGS = $(gtest_ldflags) $(SYSTEMD_LIBS)
+bus_list_names_LDADD = $(gtest_ldadd) $(SYSTEMD_LIBS)
 
 check_PROGRAMS += bus_match
 bus_match_SOURCES = bus/match.cpp
-bus_match_LDFLAGS = $(gtest_ldflags) $(SYSTEMD_LIBS)
+bus_match_LDADD = $(gtest_ldadd) $(SYSTEMD_LIBS)
 
 check_PROGRAMS += message_append
-message_append_CXXFLAGS = $(SYSTEMD_CFLAGS) $(PTHREAD_CFLAGS)
-message_append_LDFLAGS = $(SYSTEMD_LIBS) $(PTHREAD_LIBS)
 message_append_SOURCES = message/append.cpp
+message_append_CXXFLAGS = $(SYSTEMD_CFLAGS) $(PTHREAD_CFLAGS)
+message_append_LDADD = $(SYSTEMD_LIBS) $(PTHREAD_LIBS)
 
 check_PROGRAMS += message_read
-message_read_CXXFLAGS = $(SYSTEMD_CFLAGS) $(PTHREAD_CFLAGS)
-message_read_LDFLAGS = $(SYSTEMD_LIBS) $(PTHREAD_LIBS)
 message_read_SOURCES = message/read.cpp
+message_read_CXXFLAGS = $(SYSTEMD_CFLAGS) $(PTHREAD_CFLAGS)
+message_read_LDADD = $(SYSTEMD_LIBS) $(PTHREAD_LIBS)
 
 check_PROGRAMS += message_native_types
 message_native_types_SOURCES = message/native_types.cpp
-message_native_types_LDFLAGS = $(gtest_ldflags)
+message_native_types_LDADD = $(gtest_ldadd)
 
 check_PROGRAMS += message_types
 message_types_SOURCES = message/types.cpp
-message_types_LDFLAGS = $(gtest_ldflags)
+message_types_LDADD = $(gtest_ldadd)
 
 check_PROGRAMS += utility_tuple_to_array
 utility_tuple_to_array_SOURCES = utility/tuple_to_array.cpp
-utility_tuple_to_array_LDFLAGS = $(gtest_ldflags)
+utility_tuple_to_array_LDADD = $(gtest_ldadd)
 
 check_PROGRAMS += utility_type_traits
 utility_type_traits_SOURCES = utility/type_traits.cpp
 
 check_PROGRAMS += vtable_vtable
 vtable_vtable_SOURCES = vtable/vtable.cpp vtable/vtable_c.c
-vtable_vtable_LDFLAGS = $(gtest_ldflags)
+vtable_vtable_LDADD = $(gtest_ldadd)
 
 endif