tools: skip workaround for newer llvm

PR-URL: nodejs#14077
Fixes: nodejs#14076
Refs: https://svnweb.freebsd.org/ports/head/www/node/Makefile?revision=444555&view=markup
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Refael Ackermann <refack@gmail.com>

common.gypi

@@ -407,9 +407,15 @@
         'libraries': [ '-lelf' ],
       }],
       ['OS=="freebsd"', {
-        # Use this flag because on FreeBSD std::pairs copy constructor is non-trivial
-        # https://lists.freebsd.org/pipermail/freebsd-toolchain/2016-March/002094.html
-        'cflags': [ '-D_LIBCPP_TRIVIAL_PAIR_COPY_CTOR=1' ],
+        'conditions': [
+          ['llvm_version < "4.0"', {
+            # Use this flag because on FreeBSD std::pairs copy constructor is non-trivial.
+            # Doesn't apply to llvm 4.0 (FreeBSD 11.1) or later.
+            # Refs: https://lists.freebsd.org/pipermail/freebsd-toolchain/2016-March/002094.html
+            # Refs: https://svnweb.freebsd.org/ports/head/www/node/Makefile?revision=444555&view=markup
+            'cflags': [ '-D_LIBCPP_TRIVIAL_PAIR_COPY_CTOR=1' ],
+          }],
+        ],
         'ldflags': [
           '-Wl,--export-dynamic',
         ],