pspp: fix build on 10.6 and earlier

math/pspp/Portfile

@@ -43,6 +43,12 @@ depends_lib-append  path:lib/pkgconfig/cairo.pc:cairo \
 depends_build-append    port:pkgconfig \
                         port:texinfo
 
+# Need Python 2.7 or later for building, which only 10.7 and later already have
+if {${os.platform} eq "darwin" && ${os.major} <= 10} {
+    depends_build-append    port:python27
+    configure.python        ${prefix}/bin/python2.7
+}
+
 post-extract {
     if {[variant_isset gui]} {
         copy ${filespath}/PSPP ${worksrcpath}