package/memtester: fix compile and link flags

The memtester build system does not use CFLAGS/LDFLAGS variables.
Everything should be written to conf-cc and conf-ld.

Use '%' as sed expression delimiter because comma might appear in
LDFLAGS.

Cc: Matt Weber <matthew.weber@rockwellcollins.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/memtester/memtester.mk

@@ -13,8 +13,9 @@ MEMTESTER_CPE_ID_VENDOR = pryopus
 MEMTESTER_TARGET_INSTALL_OPTS = INSTALLPATH=$(TARGET_DIR)/usr
 
 define MEMTESTER_BUILD_CMDS
-	$(SED) "s,^cc,$(TARGET_CC)," $(@D)/conf-*
-	$(TARGET_MAKE_ENV) $(MAKE) $(TARGET_CONFIGURE_OPTS) -C $(@D)
+	$(SED) "s%^cc%$(TARGET_CC) $(TARGET_CFLAGS)%" $(@D)/conf-cc
+	$(SED) "s%^cc%$(TARGET_CC) $(TARGET_LDFLAGS)%" $(@D)/conf-ld
+	$(MAKE) -C $(@D)
 endef
 
 define MEMTESTER_INSTALL_TARGET_CMDS