Disable <=> tests when <compare> isn't available

.drone.jsonnet

@@ -235,6 +235,76 @@ local windows_pipeline(name, image, environment, arch = "amd64") =
         "clang-3.8",
     ),
 
+    linux_pipeline(
+        "Linux 18.04 Clang 3.9",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-3.9', CXXSTD: '03,11,14' },
+        "clang-3.9",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 Clang 4.0",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-4.0', CXXSTD: '03,11,14' },
+        "clang-4.0",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 Clang 5.0",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-5.0', CXXSTD: '03,11,14,1z' },
+        "clang-5.0",
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 Clang 6.0",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-6.0', CXXSTD: '03,11,14,17' },
+        "clang-6.0",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 7",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-7', CXXSTD: '03,11,14,17' },
+        "clang-7",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 8",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-8', CXXSTD: '03,11,14,17' },
+        "clang-8",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 9",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-9', CXXSTD: '03,11,14,17,2a' },
+        "clang-9",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 10",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-10', CXXSTD: '03,11,14,17,2a' },
+        "clang-10",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 11",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-11', CXXSTD: '03,11,14,17,2a' },
+        "clang-11",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 Clang 12",
+        "cppalliance/droneubuntu2004:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-12', CXXSTD: '03,11,14,17,2a' },
+        "clang-12",
+    ),
+
     linux_pipeline(
         "Linux 22.04 Clang 13",
         "cppalliance/droneubuntu2204:1",

include/boost/array.hpp

@@ -51,6 +51,12 @@
 #include <utility>
 #include <cstddef>
 
+#if defined(__cpp_impl_three_way_comparison) && __cpp_impl_three_way_comparison >= 201907L
+# if __has_include(<compare>)
+#  include <compare>
+# endif
+#endif
+
 namespace boost {
 
     template<class T, std::size_t N>
@@ -383,6 +389,7 @@ namespace boost {
     }
 
 #if defined(__cpp_impl_three_way_comparison) && __cpp_impl_three_way_comparison >= 201907L
+# if __has_include(<compare>)
 
     template<class T, std::size_t N>
     constexpr auto operator<=> (const array<T,N>& x, const array<T,N>& y)
@@ -394,16 +401,17 @@ namespace boost {
             if( r != 0 ) return r;
         }
 
-        return 0 <=> 0; // std::strong_ordering::equal
+        return std::strong_ordering::equal;
     }
 
     template<class T>
     constexpr auto operator<=> (const array<T,0>& /*x*/, const array<T,0>& /*y*/)
-        -> decltype( 0 <=> 0 )
+        -> std::strong_ordering
     {
-        return 0 <=> 0; // std::strong_ordering::equal
+        return std::strong_ordering::equal;
     }
 
+# endif
 #endif
 
     // undocumented and obsolete

test/array_thw_test.cpp

@@ -8,6 +8,12 @@
 #include <boost/config/pragma_message.hpp>
 #include <cstddef>
 
+#if defined(__has_include)
+# if __has_include(<compare>)
+#  define HAS_COMPARE
+# endif
+#endif
+
 #if !defined(__cpp_impl_three_way_comparison)
 
 BOOST_PRAGMA_MESSAGE( "Test skipped because __cpp_impl_three_way_comparison is not defined" )
@@ -18,6 +24,11 @@ int main() {}
 BOOST_PRAGMA_MESSAGE( "Test skipped because __cpp_impl_three_way_comparison is defined to " BOOST_STRINGIZE(__cpp_impl_three_way_comparison) )
 int main() {}
 
+#elif !defined(HAS_COMPARE)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped because <compare> is not available" )
+int main() {}
+
 #else
 
 template<class T, std::size_t N> void test()

test/array_thw_test_cx.cpp

@@ -8,6 +8,12 @@
 #include <boost/config/workaround.hpp>
 #include <cstddef>
 
+#if defined(__has_include)
+# if __has_include(<compare>)
+#  define HAS_COMPARE
+# endif
+#endif
+
 #if !defined(__cpp_impl_three_way_comparison)
 
 BOOST_PRAGMA_MESSAGE( "Test skipped because __cpp_impl_three_way_comparison is not defined" )
@@ -18,6 +24,11 @@ int main() {}
 BOOST_PRAGMA_MESSAGE( "Test skipped because __cpp_impl_three_way_comparison is defined to " BOOST_STRINGIZE(__cpp_impl_three_way_comparison) )
 int main() {}
 
+#elif !defined(HAS_COMPARE)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped because <compare> is not available" )
+int main() {}
+
 #else
 
 #define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)