Unable to install on development Python versions

[dullbananas]

Installation on stable versions of Python like 3.7 work fine, but it doesn't install on Python 3.8. This is the output that I get when trying to install on Python 3.8-dev on Travis CI:

ERROR: Complete output from command /home/travis/virtualenv/python3.8-dev/bin/python -u -c 'import setuptools, tokenize;__file__='"'"'/tmp/pip-install-ey7szdl6/pygit2/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' bdist_wheel -d /tmp/pip-wheel-bcrkw1uc --python-tag cp38:
  ERROR: running bdist_wheel
  running build
  running build_py
  creating build
  creating build/lib.linux-x86_64-3.8
  creating build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/refspec.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/ffi.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/_run.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/_build.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/credentials.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/repository.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/remote.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/submodule.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/py3.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/utils.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/config.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/index.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/__init__.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/settings.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/errors.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/blame.py -> build/lib.linux-x86_64-3.8/pygit2
  copying pygit2/py2.py -> build/lib.linux-x86_64-3.8/pygit2
  creating build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/pack.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/remote.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/revert.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/config.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/types.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/index.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/errors.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/common.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/merge.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/clone.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/refspec.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/transport.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/repository.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/net.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/stash.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/graph.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/proxy.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/oid.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/strarray.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/attr.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/diff.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/describe.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/submodule.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/blame.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/buffer.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  copying pygit2/decl/checkout.h -> build/lib.linux-x86_64-3.8/pygit2/decl
  running build_ext
  generating cffi module 'build/temp.linux-x86_64-3.8/pygit2._libgit2.c'
  creating build/temp.linux-x86_64-3.8
  building '_pygit2' extension
  creating build/temp.linux-x86_64-3.8/src
  gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -g -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -fPIC -I/usr/local/include -I/opt/python/3.8-dev/include/python3.8 -c src/blob.c -o build/temp.linux-x86_64-3.8/src/blob.o
  In file included from src/blob.c:30:0:
  src/blob.h:33:18: fatal error: git2.h: No such file or directory
  compilation terminated.
  error: command 'gcc' failed with exit status 1
  ----------------------------------------
  ERROR: Failed building wheel for pygit2
  Running setup.py clean for pygit2

[jdavid]

Added 38-dev to Travis and tests pass.

[white-gecko]

Just for the records, I had the same issue with pygit2==0.28.0 installing the 1.0.0 fixed the issue.