Fastnumber build failure on Heroku

  Building wheel for fastnumbers (setup.py) ... error
  ERROR: Command errored out with exit status 1:
   command: /app/.heroku/python/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-u6un7_3p/fastnumbers/setup.py'"'"'; __file__='"'"'/tmp/pip-install-u6un7_3p/fastnumbers/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-yjvat2p7 --python-tag cp38
       cwd: /tmp/pip-install-u6un7_3p/fastnumbers/
  Complete output (17 lines):
  running bdist_wheel
  running build
  running build_ext
  building 'fastnumbers' extension
  creating build
  creating build/temp.linux-x86_64-3.8
  creating build/temp.linux-x86_64-3.8/src
  gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -fPIC -I/tmp/pip-install-u6un7_3p/fastnumbers/include -I/app/.heroku/python/include/python3.8 -c src/fastnumbers.c -o build/temp.linux-x86_64-3.8/src/fastnumbers.o
  In file included from /usr/lib/gcc/x86_64-linux-gnu/7/include-fixed/syslimits.h:7:0,
                   from /usr/lib/gcc/x86_64-linux-gnu/7/include-fixed/limits.h:34,
                   from /app/.heroku/python/include/python3.8/Python.h:11,
                   from src/fastnumbers.c:7:
  /usr/lib/gcc/x86_64-linux-gnu/7/include-fixed/limits.h:194:15: fatal error: limits.h: No such file or directory
   #include_next <limits.h>  /* recurse down to the real one */
                 ^~~~~~~~~~
  compilation terminated.
  error: command 'gcc' failed with exit status 1
  ----------------------------------------
  ERROR: Failed building wheel for fastnumbers
  Running setup.py clean for fastnumbers
Successfully built snowfakery SQLAlchemy
Failed to build fastnumbers
ERROR: cumulusci 3.3.0 has requirement SQLAlchemy==1.3.12, but you'll have sqlalchemy 1.3.11 which is incompatible.
Installing collected packages: SQLAlchemy, fastnumbers, snowfakery
  Found existing installation: SQLAlchemy 1.3.12
    Uninstalling SQLAlchemy-1.3.12:
      Successfully uninstalled SQLAlchemy-1.3.12
    Running setup.py install for fastnumbers ... error
    ERROR: Command errored out with exit status 1:
     command: /app/.heroku/python/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-u6un7_3p/fastnumbers/setup.py'"'"'; __file__='"'"'/tmp/pip-install-u6un7_3p/fastnumbers/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-krzrbtm_/install-record.txt --single-version-externally-managed --compile
         cwd: /tmp/pip-install-u6un7_3p/fastnumbers/
    Complete output (17 lines):
    running install
    running build
    running build_ext
    building 'fastnumbers' extension
    creating build
    creating build/temp.linux-x86_64-3.8
    creating build/temp.linux-x86_64-3.8/src
    gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -fPIC -I/tmp/pip-install-u6un7_3p/fastnumbers/include -I/app/.heroku/python/include/python3.8 -c src/fastnumbers.c -o build/temp.linux-x86_64-3.8/src/fastnumbers.o
    In file included from /usr/lib/gcc/x86_64-linux-gnu/7/include-fixed/syslimits.h:7:0,
                     from /usr/lib/gcc/x86_64-linux-gnu/7/include-fixed/limits.h:34,
                     from /app/.heroku/python/include/python3.8/Python.h:11,
                     from src/fastnumbers.c:7:
    /usr/lib/gcc/x86_64-linux-gnu/7/include-fixed/limits.h:194:15: fatal error: limits.h: No such file or directory
     #include_next <limits.h>  /* recurse down to the real one */
                   ^~~~~~~~~~
    compilation terminated.
    error: command 'gcc' failed with exit status 1
    ----------------------------------------
ERROR: Command errored out with exit status 1: /app/.heroku/python/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-u6un7_3p/fastnumbers/setup.py'"'"'; __file__='"'"'/tmp/pip-install-u6un7_3p/fastnumbers/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /tmp/pip-record-krzrbtm_/install-record.txt --single-version-externally-managed --compile Check the logs for full command output.