Small Makefile improvements

- fix old build commands still using OFLAGS
- make everything work with --warn-undefined-variables, which can be useful
  for debugging typos

programs/Makefile

@@ -28,6 +28,9 @@ LOCAL_LDFLAGS += -lws2_32
 ifdef SHARED
 SHARED_SUFFIX=.$(DLEXT)
 endif
+else
+EXEXT=
+SHARED_SUFFIX=
 endif
 
 # Zlib shared library extensions:
@@ -174,11 +177,11 @@ random/gen_random_ctr_drbg$(EXEXT): random/gen_random_ctr_drbg.c ../library/libm
 
 ssl/dtls_client$(EXEXT): ssl/dtls_client.c ../library/libmbedtls.a
 	echo   "  CC    ssl/dtls_client.c"
-	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) $(OFLAGS) ssl/dtls_client.c  $(LOCAL_LDFLAGS) $(LDFLAGS) -o $@
+	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) ssl/dtls_client.c  $(LOCAL_LDFLAGS) $(LDFLAGS) -o $@
 
 ssl/dtls_server$(EXEXT): ssl/dtls_server.c ../library/libmbedtls.a
 	echo   "  CC    ssl/dtls_server.c"
-	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) $(OFLAGS) ssl/dtls_server.c  $(LOCAL_LDFLAGS) $(LDFLAGS) -o $@
+	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) ssl/dtls_server.c  $(LOCAL_LDFLAGS) $(LDFLAGS) -o $@
 
 ssl/ssl_client1$(EXEXT): ssl/ssl_client1.c ../library/libmbedtls.a
 	echo   "  CC    ssl/ssl_client1.c"
@@ -226,7 +229,7 @@ test/selftest$(EXEXT): test/selftest.c ../library/libmbedtls.a
 
 test/udp_proxy$(EXEXT): test/udp_proxy.c ../library/libmbedtls.a
 	echo   "  CC    test/udp_proxy.c"
-	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) $(OFLAGS) test/udp_proxy.c    $(LOCAL_LDFLAGS)$(LDFLAGS) -o $@
+	$(CC) $(LOCAL_CFLAGS) $(CFLAGS) test/udp_proxy.c    $(LOCAL_LDFLAGS) $(LDFLAGS) -o $@
 
 util/pem2der$(EXEXT): util/pem2der.c ../library/libmbedtls.a
 	echo   "  CC    util/pem2der.c"

tests/Makefile

@@ -37,6 +37,9 @@ LOCAL_LDFLAGS += -lws2_32
 ifdef SHARED
 SHARED_SUFFIX=.$(DLEXT)
 endif
+else
+EXEXT=
+SHARED_SUFFIX=
 endif
 
 # Zlib shared library extensions: