root6: remove redundant c++ stdlib checking block

science/root6/Portfile

@@ -185,30 +185,10 @@ if        { ${os.major} >= 18 } {
     compiler.blacklist-append macports-clang-5.0
 } else {
     # force use of MP clang 5.0
-    compiler.blacklist-append clang macports-clang-8.0 macports-clang-7.0
+    compiler.blacklist-append clang {macports-clang-[7-8].0}
     compiler.cxx_standard 2011
 }
 
-# Setup the C++ runtime on OSX10.8 (Darwin 12) and older
-if { ${os.major} <= 12 && ${configure.cxx_stdlib} ne "libc++" } {
-    # Use macports stdc++ on older systems
-    if       { ${configure.compiler} eq "macports-clang-5.0" } {
-        require_active_variants clang-5.0 libstdcxx
-    } elseif { ${configure.compiler} eq "macports-clang-6.0" } {
-        require_active_variants clang-6.0 libstdcxx
-    } elseif { ${configure.compiler} eq "macports-clang-7.0" } {
-        require_active_variants clang-7.0 libstdcxx
-    } elseif { ${configure.compiler} eq "macports-clang-8.0" } {
-        require_active_variants clang-8.0 libstdcxx
-    }
-    default_variants-append +libstdcxx
-    pre-configure {
-        foreach f [ exec find ${worksrcpath} -name "*.cmake" -or -name "*.in" -or -name "Makefile.*" ] {
-            reinplace "s|stdlib=libc++|stdlib=${configure.cxx_stdlib}|g" $f
-        }
-    }
-}
-
 # Configure the C++ runtime to use
 if { ${configure.cxx_stdlib} ne "libc++" } {
     configure.args-replace -Dlibcxx=ON -Dlibcxx=OFF