zstring_view: Add class

This adds a string_view variant that guarantees the nul terminating
character of the string is always present. Useful for c-style interface
interop.

Change-Id: Ic918d2f59e2a7a983354a7b0b4755cb033a1db5e
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/src/meson.build b/src/meson.build
index 91fecb5..bdb8f67 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -20,6 +20,7 @@
 stdplus_srcs = [
   'exception.cpp',
   'signal.cpp',
+  'zstring_view.cpp',
 ]
 
 if has_fd