Disable installation without the superproject; add comments

Simplified boolean expression

CMakeLists.txt

@@ -0,0 +1,29 @@
+# Copyright 2018 Mike Dev
+# Copyright 2019 Peter Dimov
+# Distributed under the Boost Software License, Version 1.0.
+# See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt
+
+# We support CMake 3.5, but prefer 3.16 policies and behavior
+cmake_minimum_required(VERSION 3.5...3.16)
+
+project(boost_static_assert VERSION "${BOOST_SUPERPROJECT_VERSION}" LANGUAGES CXX)
+
+add_library(boost_static_assert INTERFACE)
+add_library(Boost::static_assert ALIAS boost_static_assert)
+
+target_include_directories(boost_static_assert INTERFACE include)
+
+target_link_libraries(boost_static_assert
+    INTERFACE
+        Boost::config
+)
+
+# boost_install requires PROJECT_VERSION
+# Without the superproject, we don't have any, so skip installation
+
+if(BOOST_SUPERPROJECT_VERSION)
+
+  include(BoostInstall)
+  boost_install(TARGETS boost_static_assert HEADER_DIRECTORY include/)
+
+endif()

README.md

@@ -0,0 +1,36 @@
+Boost StaticAssert Library
+============================
+
+The Boost StaticAssert library provides static assertions for C++, this library is the ancestor to C++ native static_assert's and 
+can be used on older compilers which don't have that feature.
+
+The full documentation is available on [boost.org](http://www.boost.org/doc/libs/release/libs/static_assert).
+
+## Support, bugs and feature requests ##
+
+Bugs and feature requests can be reported through the [Gitub issue tracker](https://github.com/boostorg/static_assert/issues)
+(see [open issues](https://github.com/boostorg/static_assert/issues) and
+[closed issues](https://github.com/boostorg/static_assert/issues?utf8=%E2%9C%93&q=is%3Aissue+is%3Aclosed)).
+
+You can submit your changes through a [pull request](https://github.com/boostorg/static_assert/pulls).
+
+There is no mailing-list specific to Boost StaticAssert, although you can use the general-purpose Boost [mailing-list](http://lists.boost.org/mailman/listinfo.cgi/boost-users) using the tag [static_assert].
+
+
+## Development ##
+
+Clone the whole boost project, which includes the individual Boost projects as submodules ([see boost+git doc](https://github.com/boostorg/boost/wiki/Getting-Started)): 
+
+    git clone https://github.com/boostorg/boost
+    cd boost
+    git submodule update --init
+
+The Boost StaticAssert Library is located in `libs/static_assert/`. 
+
+### Running tests ###
+First, make sure you are in `libs/static_assert/test`. 
+You can either run all the tests listed in `Jamfile.v2` or run a single test:
+
+    ../../../b2                        <- run all tests
+    ../../../b2 static_assert_test     <- single test
+

include/boost/static_assert.hpp

@@ -53,9 +53,9 @@
 //
 #if defined(__GNUC__) && ((__GNUC__ > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 4)))
 #  ifndef BOOST_NO_CXX11_VARIADIC_MACROS
-#     define BOOST_STATIC_ASSERT_BOOL_CAST( ... ) ((__VA_ARGS__) == 0 ? false : true)
+#     define BOOST_STATIC_ASSERT_BOOL_CAST( ... ) ((__VA_ARGS__) != 0)
 #  else
-#     define BOOST_STATIC_ASSERT_BOOL_CAST( x ) ((x) == 0 ? false : true)
+#     define BOOST_STATIC_ASSERT_BOOL_CAST( x ) ((x) != 0)
 #  endif
 #else
 #  ifndef BOOST_NO_CXX11_VARIADIC_MACROS