util/cexec: Implement exception helpers

See src/stdplus/util/cexec.hpp callCheckErrno for the motivation behind
this change.

Change-Id: I0225b87398b632624f2ef8ccd6c00b5dd6b7e056
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/src/meson.build b/src/meson.build
index a6ff714..8744d33 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -23,3 +23,7 @@
   'stdplus/handle/copyable.hpp',
   'stdplus/handle/managed.hpp',
   subdir: 'stdplus/handle')
+
+install_headers(
+  'stdplus/util/cexec.hpp',
+  subdir: 'stdplus/util')