[libunwind] add hexagon support

Cr-Mirrored-From: https://chromium.googlesource.com/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 9107594f376e37e99c71881404c686b306f93ad2
diff --git a/src/UnwindCursor.hpp b/src/UnwindCursor.hpp
index 32d71c2..8200eee 100644
--- a/src/UnwindCursor.hpp
+++ b/src/UnwindCursor.hpp
@@ -1123,6 +1123,12 @@
   }
 #endif
 
+#if defined (_LIBUNWIND_TARGET_HEXAGON)
+  compact_unwind_encoding_t dwarfEncoding(Registers_hexagon &) const {
+    return 0;
+  }
+#endif
+
 #if defined (_LIBUNWIND_TARGET_MIPS_O32)
   compact_unwind_encoding_t dwarfEncoding(Registers_mips_o32 &) const {
     return 0;