Add initial support for vendor SDK 0.9.4.

Not set as default so far.

Makefile

@@ -7,6 +7,8 @@ UNZIP = unzip -q -o
 VENDOR_SDK_ZIP = $(VENDOR_SDK_ZIP_$(VENDOR_SDK))
 VENDOR_SDK_DIR = $(VENDOR_SDK_DIR_$(VENDOR_SDK))
 
+VENDOR_SDK_ZIP_0.9.4 = esp_iot_sdk_v0.9.4_14_12_19.zip
+VENDOR_SDK_DIR_0.9.4 = esp_iot_sdk_v0.9.4
 VENDOR_SDK_ZIP_0.9.3 = esp_iot_sdk_v0.9.3_14_11_21.zip
 VENDOR_SDK_DIR_0.9.3 = esp_iot_sdk_v0.9.3
 VENDOR_SDK_ZIP_0.9.2 = esp_iot_sdk_v0.9.2_14_10_24.zip
@@ -44,6 +46,9 @@ libcirom: $(TOOLCHAIN)/xtensa-lx106-elf/sysroot/lib/libcirom.a
 
 sdk_patch: .sdk_patch_$(VENDOR_SDK)
 
+.sdk_patch_0.9.4:
+	@touch $@
+
 .sdk_patch_0.9.3: esp_iot_sdk_v0.9.3_14_11_21_patch1.zip esp_iot_sdk_v0.9.3/.dir
 	$(UNZIP) $<
 	@touch $@
@@ -77,6 +82,9 @@ $(VENDOR_SDK_DIR)/.dir: $(VENDOR_SDK_ZIP)
 	-mv License $(VENDOR_SDK_DIR)
 	touch $@
 
+esp_iot_sdk_v0.9.4_14_12_19.zip:
+	wget --content-disposition "http://bbs.espressif.com/download/file.php?id=111"
+
 esp_iot_sdk_v0.9.3_14_11_21.zip:
 	wget --content-disposition "http://bbs.espressif.com/download/file.php?id=72"