alpine_socket_header_signedness.patch

--- /usr/include/sys/socket.h.ori
+++ /usr/include/sys/socket.h
@@ -265,8 +265,8 @@
 #define __MHDR_END(mhdr) ((unsigned char *)(mhdr)->msg_control + (mhdr)->msg_controllen)
 
 #define CMSG_DATA(cmsg) ((unsigned char *) (((struct cmsghdr *)(cmsg)) + 1))
-#define CMSG_NXTHDR(mhdr, cmsg) ((cmsg)->cmsg_len < sizeof (struct cmsghdr) || \
-	__CMSG_LEN(cmsg) + sizeof(struct cmsghdr) >= __MHDR_END(mhdr) - (unsigned char *)(cmsg) \
+#define CMSG_NXTHDR(mhdr, cmsg) ((unsigned)((cmsg)->cmsg_len) < sizeof (struct cmsghdr) || \
+	(unsigned)__CMSG_LEN(cmsg) + sizeof(struct cmsghdr) >= unsigned(__MHDR_END(mhdr) - (unsigned char *)(cmsg)) \
 	? 0 : (struct cmsghdr *)__CMSG_NEXT(cmsg))
 #define CMSG_FIRSTHDR(mhdr) ((size_t) (mhdr)->msg_controllen >= sizeof (struct cmsghdr) ? (struct cmsghdr *) (mhdr)->msg_control : (struct cmsghdr *) 0)