Changed every 'fpic' variant to 'pic' (#4969)

* Changed every 'fpic' variant to 'pic'. fixes #2463

Every variant that activates compilation of position independent code
has been changed to 'pic'. Hardcoded compiler flags in packages have
been substituted with `self.compiler.pic_flag`.

* Changed literal uses of '-fpic' to 'self.compiler.pic_flag'

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

@@ -47,8 +47,8 @@ class Parmgridgen(Package):
     def install(self, spec, prefix):
         make_opts = [
             'make=make',
-            'COPTIONS=-fPIC',
-            'LDOPTIONS=-fPIC',
+            'COPTIONS={0}'.format(self.compiler.pic_flag),
+            'LDOPTIONS={0}'.format(self.compiler.pic_flag),
             'CC={0}'.format(self.compiler.cc),
             'LD={0}'.format(self.compiler.cc),
             'LIBDIR=-L../..',