Python package works with sage python, but Sage package fails to load

[antonleykin]

This is related to
sagemath/cysignals#115

If M2 is compiled --with-python in sage -sh, the package Python works... but Sage fails to load.

i1 : needsPackage "Sage"
-- success: python is present
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "", line 1, in <module>
    
  File "/Users/leykin/R/sage/local/lib/python2.7/site-packages/sage/all.py", line 77, in <module>
    from cysignals.signals import (AlarmInterrupt, SignalError,
  File "/Users/leykin/R/sage/local/lib/python2.7/site-packages/cysignals/__init__.py", line 3, in <module>
    init_cysignals()
  File "src/cysignals/signals.pyx", line 251, in cysignals.signals.init_cysignals
ValueError: signal only works in main thread
../../../../M2-anton/M2/Macaulay2/packages/Sage.m2:5:6:(2):[10]: error: python error

[antonleykin]

@dimpase