add markdown-include

2 jobs for master in 1 minute and 14 seconds (queued for 1 second)
Name Stage Failure
fetch-and-build Fetch And Build
    creating build/temp.linux-x86_64-3.8/regex_3
gcc -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Os -fomit-frame-pointer -g -Os -fomit-frame-pointer -g -Os -fomit-frame-pointer -g -DTHREAD_STACK_SIZE=0x100000 -fPIC -I/usr/include/python3.8 -c regex_3/_regex.c -o build/temp.linux-x86_64-3.8/regex_3/_regex.o
unable to execute 'gcc': No such file or directory
error: command 'gcc' failed with exit status 1
ERROR: Command errored out with exit status 1: /usr/bin/python3.8 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-mo4btqq5/regex/'"'"'; __file__='"'"'/tmp/pip-install-mo4btqq5/regex/'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);'"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-6ygdyv6w/install-record.txt --single-version-externally-managed --compile Check the logs for full command output.
WARNING: You are using pip version 19.2.3, however version 20.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
ERROR: Job failed: exit code 1