build: W600-SDK importiert, Firmware-Build und Hello am EVK

Docker-Build mit gcc-arm-none-eabi 4.9-2014q4 (statt Homebrew-Cask) verwendet,
Dockerfile/tools/docker.sh dafür aus Task 13 vorgezogen. cmake/sdk.cmake schont
gcc 4.9 (kennt -fcommon/-Wno-error=... nicht). Zwei zusätzliche SDK-Stubs
(EarlyInit, pre_gpio_config) in src/sys/sdk_stubs.c ergänzt, siehe sdk/PATCHES.md.

sdk/Platform/Inc/rc4.h

@@ -0,0 +1,38 @@
+#ifndef RC4_H
+#define RC4_H
+#include "wm_crypto_hard.h"
+
+void Arc4Init(psCipherContext_t *ctx, unsigned char *key, uint32 keylen);
+int32 Arc4_skip(psCipherContext_t *ctx, unsigned char *in,
+			   unsigned char *out, size_t skip, uint32 len);
+/**
+ * rc4_skip - XOR RC4 stream to given data with skip-stream-start
+ * @key: RC4 key
+ * @keylen: RC4 key length
+ * @skip: number of bytes to skip from the beginning of the RC4 stream
+ * @data: data to be XOR'ed with RC4 stream
+ * @data_len: buf length
+ * Returns: 0 on success, -1 on failure
+ *
+ * Generate RC4 pseudo random stream for the given key, skip beginning of the
+ * stream, and XOR the end result with the data buffer to perform RC4
+ * encryption/decryption.
+ */
+int rc4_skip(const u8 *key, size_t keylen, size_t skip,
+	     u8 *data, size_t data_len);
+/**
+ * rc4 - XOR RC4 stream to given data with skip-stream-start
+ * @key: RC4 key
+ * @keylen: RC4 key length
+ * @data: data to be XOR'ed with RC4 stream
+ * @data_len: buf length
+ * Returns: 0 on success, -1 on failure
+ *
+ * Generate RC4 pseudo random stream for the given key, skip beginning of the
+ * stream, and XOR the end result with the data buffer to perform RC4
+ * encryption/decryption.
+ */
+
+int rc4(const u8 *key, size_t keylen, u8 *data, size_t data_len);
+
+#endif /* end of RC4_H */