kcat: fix build on older OS

net/kcat/Portfile

@@ -5,7 +5,6 @@ PortGroup           github 1.0
 
 github.setup        edenhill kcat 1.7.1
 categories          net
-platforms           darwin
 license             BSD
 maintainers         {gmail.com:alexey.trenikhin+macports @alexeyt820} \
                     openmaintainer
@@ -20,3 +19,14 @@ configure.args      --enable-json
 
 depends_lib         port:yajl \
                     port:librdkafka
+
+# configure fails with gcc-4.2
+compiler.blacklist-append \
+                    *gcc-4.*
+
+# https://github.com/edenhill/kcat/issues/448
+if {[string match *gcc* ${configure.compiler}] \
+    && ${configure.build_arch} in [list arm i386 ppc]} {
+    configure.ldflags-append \
+                    -latomic
+}