Fuchsia: Initial check-in.

runtime/vm/signal_handler.h

Index: runtime/vm/signal_handler.h
diff --git a/runtime/vm/signal_handler.h b/runtime/vm/signal_handler.h
index ecdfe02ccc30d8cc95de32ad6455313b1f0fb82f..615e584839397707135c12b6e617d8e238798d87 100644
--- a/runtime/vm/signal_handler.h
+++ b/runtime/vm/signal_handler.h
@@ -34,6 +34,9 @@ struct siginfo_t;
 struct mcontext_t;
 struct sigset_t {
 };
+#elif defined(TARGET_OS_FUCHSIA)
+#include <signal.h>  // NOLINT
+#include <ucontext.h>  // NOLINT
 #endif
 
 
@@ -84,7 +87,8 @@ class SignalHandler : public AllStatic {
   // that no actual instructions are skipped and then branch to the actual
   // signal handler.
   //
-  // For the kernel patch that fixes the issue see: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6ecf830e5029598732e04067e325d946097519cb
+  // For the kernel patch that fixes the issue see:
+  // http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6ecf830e5029598732e04067e325d946097519cb
   //
   // Note: this function is marked "naked" because we must guarantee that
   // our NOPs occur before any compiler generated prologue.