Add support for using C++17 string_view or a fallback

Define a `cm::string_view` type implemented via C++17 `std::string_view`
when available.  Provide a fallback implementation for C++11 and C++14
compilers.

The fallback implementation was written by reading documentation of the
standard spec.  We have no dedicated tests for it, but it will be
covered by tests of its clients later.

1 files changed, 1 insertions, 0 deletions

diff --git a/bootstrap b/bootstrap
index 6710d1a..dcc3a83 100755
--- a/bootstrap
+++ b/bootstrap
@@ -430,6 +430,7 @@ CMAKE_CXX_SOURCES="\
   cmake  \
   cmakemain \
   cmcmd  \
+  cm_string_view \
 "
 
 if ${cmake_system_mingw}; then