Merge branch 'msvc-C5045' into 'master'

mitigate C5045

See merge request correaa/boost-multi!1355

include/boost/multi/detail/layout.hpp

@@ -206,8 +206,8 @@ struct extensions_t : boost::multi::detail::tuple_prepend_t<index_extension, typ
 	template<class... Indices>
 	constexpr auto prev_canonical(index& idx, Indices&... rest) const -> bool {  // NOLINT(google-runtime-references) idx is mutated
 		if(extensions_t<D-1>{this->base().tail()}.prev_canonical(rest...)) { --idx; }
-		if(idx < this->base().head().first()) {
-			idx = this->base().head().back();
+		if(idx < static_cast<index>(this->base().head().first())) {
+			idx = static_cast<index>(this->base().head().back());
 			return true;
 		}
 		return false;

test/CMakeLists.txt

@@ -329,6 +329,7 @@ else()
 	/wd4868  # compiler may not enforce left-to-right evaluation order in braced initializer list
 	/wd5026  # move constructor was implicitly defined as deleted
 	/wd5027  # move assignment operator was implicitly defined as deleted
+	/wd5045  # Compiler will insert Spectre mitigation for memory load if /Qspectre switch specified
 	>
 	)