imports: Switch to Microsoft GSL implementation

... with two minor code base changes compared to previous
use of gsl-lite:

- dag.hpp: ActionNode::Ptr and ArtifactNode::Ptr are not
  wrapped in gsl::not_null<> anymore, due to lack of support
  for wrapping std::unique_ptr<>. More specifically, the
  move constructor is missing, rendering it impossible to
  use std::vector<>::emplace_back().

- utils/cpp/gsl.hpp: New header file added to implement the
  macros ExpectsAudit() and EnsureAudit(), asserts running
  only in debug builds, which were available in gsl-lite but
  are missing in MS GSL.

1 files changed, 3 insertions, 2 deletions

diff --git a/src/buildtool/build_engine/expression/expression.cpp b/src/buildtool/build_engine/expression/expression.cpp
index 191af619..1cb27a69 100644
--- a/src/buildtool/build_engine/expression/expression.cpp
+++ b/src/buildtool/build_engine/expression/expression.cpp
@@ -21,9 +21,10 @@
 #include <type_traits>
 
 #include "fmt/core.h"
-#include "gsl-lite/gsl-lite.hpp"
+#include "gsl/gsl"
 #include "src/buildtool/build_engine/expression/evaluator.hpp"
 #include "src/buildtool/logging/logger.hpp"
+#include "src/utils/cpp/gsl.hpp"
 #include "src/utils/cpp/json.hpp"
 
 auto Expression::operator[](
@@ -208,7 +209,7 @@ auto Expression::FromJson(nlohmann::json const& json) noexcept
             return ExpressionPtr{Expression::map_t{m}};
         }
     } catch (...) {
-        gsl_EnsuresAudit(false);  // ensure that the try-block never throws
+        EnsuresAudit(false);  // ensure that the try-block never throws
     }
     return ExpressionPtr{nullptr};
 }