Split `satisfies(..., strict=True/False)` into two functions (#35681)

This commit formalizes `satisfies(lhs, rhs, strict=True/False)`
and splits it into two functions: `satisfies(lhs, rhs)` and
`intersects(lhs, rhs)`.

- `satisfies(lhs, rhs)` means: all concrete specs matching the
   left hand side also match the right hand side
- `intersects(lhs, rhs)` means: there exist concrete specs
   matching both lhs and rhs.

`intersects` now has the property that it's commutative,
which previously was not guaranteed.

For abstract specs, `intersects(lhs, rhs)` implies that
`constrain(lhs, rhs)` works.

What's *not* done in this PR is ensuring that
`intersects(concrete, abstract)` returns false when the
abstract spec has additional properties not present in the
concrete spec, but `constrain(concrete, abstract)` will
raise an error.

To accomplish this, some semantics have changed, as well
as bugfixes to ArchSpec:
- GitVersion is now interpreted as a more constrained
  version
- Compiler flags are interpreted as strings since their
  order is important
- Abstract specs respect variant type (bool / multivalued)

1 files changed, 1 insertions, 1 deletions

diff --git a/var/spack/repos/builtin/packages/macsio/package.py b/var/spack/repos/builtin/packages/macsio/package.py
index e2e91b90c9..188e817b1c 100644
--- a/var/spack/repos/builtin/packages/macsio/package.py
+++ b/var/spack/repos/builtin/packages/macsio/package.py
@@ -21,7 +21,7 @@ class Macsio(CMakePackage):
     version("1.0", sha256="1dd0df28f9f31510329d5874c1519c745b5c6bec12e102cea3e9f4b05e5d3072")
 
     variant("mpi", default=True, description="Build MPI plugin")
-    variant("silo", default=True, description="Build with SILO plugin")
+    variant("silo", default=False, description="Build with SILO plugin")
     # TODO: multi-level variants for hdf5
     variant("hdf5", default=False, description="Build HDF5 plugin")
     variant("zfp", default=False, description="Build HDF5 with ZFP compression")