Define sockaddr_storage in bionic

Bionic currently renames the kernel's __kernel_sockaddr_storage
to sockaddr_storage.  We would like to reuse the bionic kernel
headers for musl, but musl defines its own sockaddr_storage,
causing redefinition errors when the musl and kernel headers
are both included.

Give bionic its own definition of sockaddr_storage so the kernel
one can be left as __kernel_sockaddr_storage, avoiding the
conflict in musl.

Some of the structs in netinet/in.h contain sockaddr_storage members.
There are definitions in linux/in.h, but they now use the
__kernel_sockaddr_storage naming.  To avoid having to copy the structs
from linux/in.h into netinet/in.h, add some #define hackery to
rename __kernel_sockaddr_storage to sockaddr_storage when including
linux/in.h from netinet/in.h.

Bug: 190084016
Test: m checkbuild
Test: bionic-unit-tests
Change-Id: I8f654511722b3a4a8e0bb146e4418ebcd370305c
diff --git a/libc/kernel/uapi/linux/in.h b/libc/kernel/uapi/linux/in.h
index 10c6416..6f11f52 100644
--- a/libc/kernel/uapi/linux/in.h
+++ b/libc/kernel/uapi/linux/in.h
@@ -155,21 +155,21 @@
 #define IP_MSFILTER_SIZE(numsrc) (sizeof(struct ip_msfilter) - sizeof(__u32) + (numsrc) * sizeof(__u32))
 struct group_req {
   __u32 gr_interface;
-  struct sockaddr_storage gr_group;
+  struct __kernel_sockaddr_storage gr_group;
 };
 struct group_source_req {
   __u32 gsr_interface;
-  struct sockaddr_storage gsr_group;
-  struct sockaddr_storage gsr_source;
+  struct __kernel_sockaddr_storage gsr_group;
+  struct __kernel_sockaddr_storage gsr_source;
 };
 struct group_filter {
   __u32 gf_interface;
-  struct sockaddr_storage gf_group;
+  struct __kernel_sockaddr_storage gf_group;
   __u32 gf_fmode;
   __u32 gf_numsrc;
-  struct sockaddr_storage gf_slist[1];
+  struct __kernel_sockaddr_storage gf_slist[1];
 };
-#define GROUP_FILTER_SIZE(numsrc) (sizeof(struct group_filter) - sizeof(struct sockaddr_storage) + (numsrc) * sizeof(struct sockaddr_storage))
+#define GROUP_FILTER_SIZE(numsrc) (sizeof(struct group_filter) - sizeof(struct __kernel_sockaddr_storage) + (numsrc) * sizeof(struct __kernel_sockaddr_storage))
 #endif
 #if __UAPI_DEF_IN_PKTINFO
 struct in_pktinfo {