Backport and edit of patches from:
https://gcc.gnu.org/viewcvs/gcc?limit_changes=0&view=revision&revision=249957
by jsm28 (Joseph Myers)

Current glibc no longer gives the ucontext_t type the tag struct
ucontext, to conform with POSIX namespace rules.  This requires
various linux-unwind.h files in libgcc, that were previously using
struct ucontext, to be fixed to use ucontext_t instead.  This is
similar to the removal of the struct siginfo tag from siginfo_t some
years ago.

This patch changes those files to use ucontext_t instead.  As the
standard name that should be unconditionally safe, so this is not
restricted to architectures supported by glibc, or conditioned on the
glibc version.

Upstream-Status: Backport

Signed-off-by: Juro Bystricky <juro.bystricky@intel.com>

--- branches/gcc-6-branch/libgcc/config/aarch64/linux-unwind.h	2017/07/04 10:22:56	249956
--- b/libgcc/config/aarch64/linux-unwind.h	2017/07/04 10:23:57	249957
@@ -52,7 +52,7 @@
   struct rt_sigframe
   {
     siginfo_t info;
-    struct ucontext uc;
+    ucontext_t uc;
   };
 
   struct rt_sigframe *rt_;
--- branches/gcc-6-branch/libgcc/config/alpha/linux-unwind.h	2017/07/04 10:22:56	249956
--- b/libgcc/config/alpha/linux-unwind.h	2017/07/04 10:23:57	249957
@@ -51,7 +51,7 @@
     {
       struct rt_sigframe {
 	siginfo_t info;
-	struct ucontext uc;
+	ucontext_t uc;
       } *rt_ = context->cfa;
       sc = &rt_->uc.uc_mcontext;
     }
--- branches/gcc-6-branch/libgcc/config/bfin/linux-unwind.h	2017/07/04 10:22:56	249956
--- b/libgcc/config/bfin/linux-unwind.h	2017/07/04 10:23:57	249957
@@ -52,7 +52,7 @@
 	void *puc;
 	char retcode[8];
 	siginfo_t info;
-	struct ucontext uc;
+	ucontext_t uc;
       } *rt_ = context->cfa;
 
       /* The void * cast is necessary to avoid an aliasing warning.
--- branches/gcc-6-branch/libgcc/config/i386/linux-unwind.h	2017/07/04 10:22:56	249956
--- b/libgcc/config/i386/linux-unwind.h	2017/07/04 10:23:57	249957
@@ -58,7 +58,7 @@
   if (*(unsigned char *)(pc+0) == 0x48
       && *(unsigned long long *)(pc+1) == RT_SIGRETURN_SYSCALL)
     {
-      struct ucontext *uc_ = context->cfa;
+      ucontext_t *uc_ = context->cfa;
       /* The void * cast is necessary to avoid an aliasing warning.
          The aliasing warning is correct, but should not be a problem
          because it does not alias anything.  */
@@ -138,7 +138,7 @@
 	siginfo_t *pinfo;
 	void *puc;
 	siginfo_t info;
-	struct ucontext uc;
+	ucontext_t uc;
       } *rt_ = context->cfa;
       /* The void * cast is necessary to avoid an aliasing warning.
          The aliasing warning is correct, but should not be a problem
--- branches/gcc-6-branch/libgcc/config/m68k/linux-unwind.h	2017/07/04 10:22:56	249956
--- b/libgcc/config/m68k/linux-unwind.h	2017/07/04 10:23:57	249957
@@ -33,7 +33,7 @@
 /* <sys/ucontext.h> is unfortunately broken right now.  */
 struct uw_ucontext {
 	unsigned long	  uc_flags;
-	struct ucontext  *uc_link;
+	ucontext_t	 *uc_link;
 	stack_t		  uc_stack;
 	mcontext_t	  uc_mcontext;
 	unsigned long	  uc_filler[80];
--- branches/gcc-6-branch/libgcc/config/nios2/linux-unwind.h	2017/07/04 10:22:56	249956
--- b/libgcc/config/nios2/linux-unwind.h	2017/07/04 10:23:57	249957
@@ -38,7 +38,7 @@
 
 struct nios2_ucontext {
   unsigned long uc_flags;
-  struct ucontext *uc_link;
+  ucontext_t *uc_link;
   stack_t uc_stack;
   struct nios2_mcontext uc_mcontext;
   sigset_t uc_sigmask;	/* mask last for extensibility */
--- branches/gcc-6-branch/libgcc/config/pa/linux-unwind.h	2017/07/04 10:22:56	249956
--- b/libgcc/config/pa/linux-unwind.h	2017/07/04 10:23:57	249957
@@ -80,7 +80,7 @@
   struct sigcontext *sc;
   struct rt_sigframe {
     siginfo_t info;
-    struct ucontext uc;
+    ucontext_t uc;
   } *frame;
 
   /* rt_sigreturn trampoline:
--- branches/gcc-6-branch/libgcc/config/sh/linux-unwind.h	2017/07/04 10:22:56	249956
--- b/libgcc/config/sh/linux-unwind.h	2017/07/04 10:23:57	249957
@@ -180,7 +180,7 @@
     {
       struct rt_sigframe {
 	siginfo_t info;
-	struct ucontext uc;
+	ucontext_t uc;
       } *rt_ = context->cfa;
       /* The void * cast is necessary to avoid an aliasing warning.
          The aliasing warning is correct, but should not be a problem
--- branches/gcc-6-branch/libgcc/config/tilepro/linux-unwind.h	2017/07/04 10:22:56	249956
--- b/libgcc/config/tilepro/linux-unwind.h	2017/07/04 10:23:57	249957
@@ -61,7 +61,7 @@
   struct rt_sigframe {
     unsigned char save_area[C_ABI_SAVE_AREA_SIZE];
     siginfo_t info;
-    struct ucontext uc;
+    ucontext_t uc;
   } *rt_;
 
   /* Return if this is not a signal handler.  */
--- branches/gcc-6-branch/libgcc/config/xtensa/linux-unwind.h	2017/07/04 10:22:56	249956
--- b/libgcc/config/xtensa/linux-unwind.h	2017/07/04 10:23:57	249957
@@ -67,7 +67,7 @@
 
   struct rt_sigframe {
     siginfo_t info;
-    struct ucontext uc;
+    ucontext_t uc;
   } *rt_;
 
   /* movi a2, __NR_rt_sigreturn; syscall */