Merge upstream master in libre-soc master.

diff --cc setup.py
index 78796093ccbb27dc22fc37d657141efd174fa05e,0f22531daf6f41a9d7cb2f84768a91a06ff7b034..b57c2e4587251ef5acd8da52d0ca8f77b4631e4d
--- 1/setup.py
--- 2/setup.py
+++ b/setup.py
@@@ -23,13 -23,7 +23,13 @@@ setup
      license="multi",
      python_requires="~=3.6",
      setup_requires=["setuptools_scm"],
 -    install_requires=["setuptools", "cocotb", "nmigen", "nmigen-soc"],
 +
 +    # removing cocotb, causing unnecessary dependency and install problems
-     install_requires=["setuptools", "nmigen", "modgrammar"],
++    install_requires=["setuptools", "nmigen", "nmigen-soc", "modgrammar"],
 +
 +    # unit tests require cocotb: main operation does not
 +    tests_require=['cocotb'],
 +
      include_package_data=True,
      packages=find_packages(),
      project_urls={