Avoid a deadlock when running MT

This fix may be better as a reentrant mutex that is conditionally applied only to mt_preview compiled code, but I like the fact that spinlocks become no-ops unless running multithreaded, and they are very simple.
Also bump the version for a new release, and made a couple code cleanliness tweaks.

VERSION

@@ -1 +1 @@
-1.0.0
+1.0.1

shard.yml

@@ -1,5 +1,5 @@
 name: csuuid
-version: 1.0.0
+version: 1.0.1
 
 authors:
  - Kirk Haines <[email protected]>
@@ -18,4 +18,4 @@ dependencies:
 development_dependencies:
  ameba:
  github: crystal-ameba/ameba
- version: ~> 1.5
+ version: ~> 1.6

src/csuuid.cr

@@ -58,6 +58,7 @@ struct CSUUID
  # It defaults to `Random::ISAAC`.
  class_property prng : Random = Random::ISAAC.new
  @@mutex = Crystal::SpinLock.new
+ @@isaac_mutex = Crystal::SpinLock.new
  @@unique_identifier : Slice(UInt8) = Slice(UInt8).new(6, 0)
  @@unique_seconds_and_nanoseconds : Tuple(Int64, Int32) = {0_i64, 0_i32}
 
@@ -153,11 +154,11 @@ struct CSUUID
 
  IO::ByteFormat::BigEndian.encode(seconds, @bytes[2, 8])
  IO::ByteFormat::BigEndian.encode(nanoseconds, @bytes[0, 4])
- @@mutex.sync do
+ @@isaac_mutex.sync do
  # Random::ISAAC.random_bytes doesn't appear to be threadsafe.
  # It sometimes dies ugly in multithreaded code, so we need a
  # lock in this one tiny little space to avoid that.
- # TODO: Check if this is still the case post Crystal 1.4.0,
+ # Check if this is still the case post Crystal 1.4.0,
  # and if it is, fix Crypt::ISAAC and send in a PR.
  @bytes[10, 6].copy_from(id || CSUUID.prng.random_bytes(6))
  end
@@ -201,16 +202,16 @@ struct CSUUID
 
  # Compare two CSUUID objects, returning -1 if the first is less than the second,
  # 0 if they are equal, and 1 if the first is greater than the second.
- def <=>(val : CSUUID)
+ def <=>(other : CSUUID)
  s, ns = seconds_and_nanoseconds
- s_val, ns_val = val.seconds_and_nanoseconds
+ s_val, ns_val = other.seconds_and_nanoseconds
  r = s <=> s_val
  return r unless r == 0
 
  r = ns <=> ns_val
  return r unless r == 0
 
- to_s <=> val.to_s
+ to_s <=> other.to_s
  end
 
  # Returns `true` if `self` is less than *other*.