Rollback trunk to 3.21.15.

src/platform-solaris.cc

Index: src/platform-solaris.cc
diff --git a/src/platform-solaris.cc b/src/platform-solaris.cc
index df81c3a6bc87fc82042eb45138afeafe570f19d0..f082af125404693b71cf528d573c5bb63e2f8588 100644
--- a/src/platform-solaris.cc
+++ b/src/platform-solaris.cc
@@ -211,6 +211,20 @@ static int StackWalkCallback(uintptr_t pc, int signo, void* data) {
 }
 
 
+int OS::StackWalk(Vector<OS::StackFrame> frames) {
+  ucontext_t ctx;
+  struct StackWalker walker = { frames, 0 };
+
+  if (getcontext(&ctx) < 0) return kStackWalkError;
+
+  if (!walkcontext(&ctx, StackWalkCallback, &walker)) {
+    return kStackWalkError;
+  }
+
+  return walker.index;
+}
+
+
 // Constants used for mmap.
 static const int kMmapFd = -1;
 static const int kMmapFdOffset = 0;