py-tables: allow building on old systems

python/py-tables/Portfile

@@ -20,9 +20,15 @@ long_description    PyTables is a package for managing hierarchical datasets \
 
 homepage            https://www.pytables.org/
 
-checksums           md5 7557f426070725fd93cf33740eb3d229 \
-                    rmd160 9c5ff800403559316b9d6b6c766d86b219f38177 \
-                    sha256 d470263c2e50c4b7c8635a0d99ac1ff2f9e704c24d71e5fa33c4529e7d0ad9c3
+checksums           rmd160  9c5ff800403559316b9d6b6c766d86b219f38177 \
+                    sha256  d470263c2e50c4b7c8635a0d99ac1ff2f9e704c24d71e5fa33c4529e7d0ad9c3 \
+                    size    4683437
+
+# The build picks gcc-4.2, which fails.
+# Modern MPICH needs a modern GCC version.
+# error: command '/usr/bin/gcc-4.2' failed with exit code 1
+compiler.blacklist-append \
+                    *gcc-4.0 *gcc-4.2
 
 mpi.setup