Change __BORLANDC__ to BOOST_BORLANDC, which is defined in Boost config for the Embarcadero non-clang-based compilers.

test/concepts/concept_check.cpp

@@ -15,7 +15,7 @@
 // this lets us compile at warning level 4 without seeing concept-check related warnings
 #  pragma warning(disable:4100)
 #endif
-#ifdef __BORLANDC__
+#ifdef BOOST_BORLANDC
 #pragma option -w-8019 -w-8004 -w-8008
 #endif
 #ifdef BOOST_INTEL
@@ -53,7 +53,7 @@ int main()
    >();
 #endif
 #endif
-#if !BOOST_WORKAROUND(__BORLANDC__, < 0x560)
+#if !BOOST_WORKAROUND(BOOST_BORLANDC, < 0x560)
    boost::function_requires<
       boost::BoostRegexConcept<
          boost::basic_regex<char, boost::c_regex_traits<char> >