mongoose: bump to version 5.4

Avoid compilation of the server via the upstream Makefile which
unconditionally uses -lssl

The -lssl flag is appended to MONGOOSE_CFLAGS whenever
BR2_PACKAGE_OPENSSL=y gets set.

Signed-off-by: Davide Viti <zinosat@tiscali.it>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/mongoose/mongoose.mk

@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-MONGOOSE_VERSION = 5.3
+MONGOOSE_VERSION = 5.4
 MONGOOSE_SITE = $(call github,cesanta,mongoose,$(MONGOOSE_VERSION))
 MONGOOSE_LICENSE = GPLv2
 MONGOOSE_LICENSE_FILES = LICENSE
@@ -19,8 +19,8 @@ MONGOOSE_CFLAGS += -DNS_ENABLE_SSL -lssl -lcrypto -lz
 endif
 
 define MONGOOSE_BUILD_CMDS
-	$(MAKE) CC="$(TARGET_CC)" LD="$(TARGET_LD)" -C $(@D)/examples \
-		CFLAGS_EXTRA="$(MONGOOSE_CFLAGS)" server
+	$(TARGET_CC) $(@D)/examples/server.c $(@D)/mongoose.c \
+		-o $(@D)/examples/server $(MONGOOSE_CFLAGS) -pthread -ldl
 	$(TARGET_CC) -c $(@D)/mongoose.c $(MONGOOSE_CFLAGS) -o $(@D)/mongoose.o
 	$(TARGET_AR) rcs $(@D)/libmongoose.a $(@D)/mongoose.o
 endef