Parquet: new packages (#8601)

* parquet: new package

Includes the following dependencies:

* arrow
* flatbuffers

Changes for compilation:

* snappy
* thrift
* zstd

* parquet: improve recipes (including dependencies)

* arrow: remove unused import in recipe

* parquet: fix line length for flake8/py27

* parquet, arrow: fix py26 format strings

* Address review comments.

* arrow: simplify recipe

var/spack/repos/builtin/packages/snappy/package.py

@@ -34,6 +34,7 @@ class Snappy(CMakePackage):
     version('1.1.7', 'ee9086291c9ae8deb4dac5e0b85bf54a')
 
     variant('shared', default=True, description='Build shared libraries')
+    variant('pic', default=True, description='Build position independent code')
 
     def cmake_args(self):
         spec = self.spec
@@ -47,6 +48,12 @@ def cmake_args(self):
 
         return args
 
+    def flag_handler(self, name, flags):
+        flags = list(flags)
+        if '+pic' in self.spec and name in ('cflags', 'cxxflags'):
+            flags.append(self.compiler.pic_flag)
+        return (None, None, flags)
+
     @run_after('install')
     def install_pkgconfig(self):
         mkdirp(self.prefix.lib.pkgconfig)