Fix #if tests for PTRACE_GETREGS and others.

[foad]

Summary

On PowerPC64 Linux PTRACE_GETREGS is a #define and PT_GETREGS is not.
On other systems it's the other way round. Extend the #ifs to check for
both PTRACE_* and PT_*.

This fixes test/sanitizer_common/TestCases/Linux/ptrace.cc when msan is
enabled for PowerPC64.

[samsonov]

LGTM

lib/sanitizer_common/sanitizer_platform_limits_posix.cc

#ifdef __arm__
   unsigned struct_user_vfpregs_struct_sz = ARM_VFPREGS_SIZE;
 #else
   unsigned struct_user_vfpregs_struct_sz = 0;
 #endif
 
   int ptrace_peektext = PTRACE_PEEKTEXT;
   int ptrace_peekdata = PTRACE_PEEKDATA;
   int ptrace_peekuser = PTRACE_PEEKUSER;
-#if defined(PT_GETREGS) && defined(PT_SETREGS)
+#if (defined(PTRACE_GETREGS) && defined(PTRACE_SETREGS)) || \
+    (defined(PT_GETREGS) && defined(PT_SETREGS))
   int ptrace_getregs = PTRACE_GETREGS;
   int ptrace_setregs = PTRACE_SETREGS;
 #else
   int ptrace_getregs = -1;
   int ptrace_setregs = -1;
 #endif
-#if defined(PT_GETFPREGS) && defined(PT_SETFPREGS)
+#if (defined(PTRACE_GETFPREGS) && defined(PTRACE_SETFPREGS)) || \
+    (defined(PT_GETFPREGS) && defined(PT_SETFPREGS))
   int ptrace_getfpregs = PTRACE_GETFPREGS;
   int ptrace_setfpregs = PTRACE_SETFPREGS;
 #else
   int ptrace_getfpregs = -1;
   int ptrace_setfpregs = -1;
 #endif
-#if defined(PT_GETFPXREGS) && defined(PT_SETFPXREGS)
+#if (defined(PTRACE_GETFPXREGS) && defined(PTRACE_SETFPXREGS)) || \
+    (defined(PT_GETFPXREGS) && defined(PT_SETFPXREGS))
   int ptrace_getfpxregs = PTRACE_GETFPXREGS;
   int ptrace_setfpxregs = PTRACE_SETFPXREGS;
 #else
   int ptrace_getfpxregs = -1;
   int ptrace_setfpxregs = -1;
 #endif // PTRACE_GETFPXREGS/PTRACE_SETFPXREGS
 #if defined(PTRACE_GETVFPREGS) && defined(PTRACE_SETVFPREGS)
   int ptrace_getvfpregs = PTRACE_GETVFPREGS;