rem: md5_init_ctx (ctx) struct md5_ctx *ctx;
add: md5_init_ctx (struct md5_ctx *ctx)
context: md5_init_ctx (ctx)     struct md5_ctx *ctx;{  ctx->A = 0x67452301;  ctx->B = 0xefcdab89;  ctx->C = 0x98badcfe;  ctx->D = 0x10325476;  ctx->total[0] = ctx->total[1] = 0;  ctx->buflen = 0;}