Test suite fails (with old Keyword::Declare?)

The test suite fails on some of my smokers:
```
# Failed test 'use Sub::Alias;'
# at t/00.load.t line 4.
# Tried to use 'Sub::Alias'.
# Error: Unknown type (VariableScalar) in parameter list of keyword alias at /home/cpansand/.cpan/build/2020040704/Sub-Alias-1.0.0-0/blib/lib/Sub/Alias.pm line 34.
# Compilation failed in require at t/00.load.t line 4.
# BEGIN failed--compilation aborted at t/00.load.t line 4.
# Testing Sub::Alias
# Looks like you failed 1 test of 1.
t/00.load.t ....
Dubious, test returned 1 (wstat 256, 0x100)
Failed 1/1 subtests
Unknown type (VariableScalar) in parameter list of keyword alias at /home/cpansand/.cpan/build/2020040704/Sub-Alias-1.0.0-0/blib/lib/Sub/Alias.pm line 34.
Compilation failed in require at t/byref.t line 5.
BEGIN failed--compilation aborted at t/byref.t line 5.
# Looks like your test exited with 255 before it could output anything.
t/byref.t ......
Dubious, test returned 255 (wstat 65280, 0xff00)
Failed 4/4 subtests
... (etc) ...
```

This happens if older Keyword::Declare is installed. Statistical analysis:
```
****************************************************************
Regression 'mod:Keyword::Declare'
****************************************************************
Name Theta StdErr T-stat
[0='const'] 0.0000 0.0000 29.79
[1='eq_0.000005'] 0.0000 0.0000 7.51
[2='eq_0.001006'] 1.0000 0.0000 44721605021501832.00
[3='eq_0.001010'] 1.0000 0.0000 44721605021501824.00
[4='eq_0.001013'] 1.0000 0.0000 44721605021501816.00
[5='eq_0.001014'] 1.0000 0.0000 76277425817254800.00
[6='eq_0.001015'] 1.0000 0.0000 56568852994547672.00
[7='eq_0.001017'] 1.0000 0.0000 86923175846883040.00

R^2= 1.000, N= 71, K= 8
****************************************************************
```