[PATCH] selftests/powerpc: Fix: use ucontext_t instead of struct ucontext

[Harish]

With glibc 2.26 'struct ucontext' is removed to improve POSIX
compliance, which breaks powerpc/alignment_handler selftest.
Fix the test by using ucontext_t. Tested on ppc, works with older
glibc versions as well.

Fixes the following:
alignment_handler.c: In function ‘sighandler’:
alignment_handler.c:68:5: error: dereferencing pointer to incomplete type 
‘struct ucontext’
  ucp->uc_mcontext.gp_regs[PT_NIP] += 4;
     ^~

Signed-off-by: Harish <har...@linux.vnet.ibm.com>
---
 tools/testing/selftests/powerpc/alignment/alignment_handler.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/powerpc/alignment/alignment_handler.c 
b/tools/testing/selftests/powerpc/alignment/alignment_handler.c
index 39fd362..0f2698f 100644
--- a/tools/testing/selftests/powerpc/alignment/alignment_handler.c
+++ b/tools/testing/selftests/powerpc/alignment/alignment_handler.c
@@ -57,7 +57,7 @@ volatile int gotsig;
 
 void sighandler(int sig, siginfo_t *info, void *ctx)
 {
-       struct ucontext *ucp = ctx;
+       ucontext_t *ucp = ctx;
 
        if (!testing) {
                signal(sig, SIG_DFL);
-- 
2.7.4