ifeffit @1.2.13_7+gcc11 build failure due to implicit declarations

[maxwilke]

Cannot install ifeffit on macOS Big Sur. Checked also gcc10 and gcc9. Installation fails with following message:

--->  Fetching archive for ifeffit
--->  Attempting to fetch ifeffit-1.2.13_7+gcc11.darwin_20.x86_64.tbz2 from https://packages.macports.org/ifeffit
--->  Attempting to fetch ifeffit-1.2.13_7+gcc11.darwin_20.x86_64.tbz2 from https://nue.de.packages.macports.org/ifeffit
--->  Attempting to fetch ifeffit-1.2.13_7+gcc11.darwin_20.x86_64.tbz2 from https://fra.de.packages.macports.org/ifeffit
--->  Fetching distfiles for ifeffit
--->  Verifying checksums for ifeffit
--->  Extracting ifeffit
--->  Configuring ifeffit
Warning: Configuration logfiles contain indications of -Wimplicit-function-declaration; check that features were not accidentally disabled:
  strcmp: found in newville-ifeffit-83b3455/readline/config.log
  exit: found in newville-ifeffit-83b3455/config.log, newville-ifeffit-83b3455/readline/config.log
  strcoll: found in newville-ifeffit-83b3455/readline/config.log
--->  Building ifeffit
Error: Failed to build ifeffit: command execution failed
Error: See /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_science_ifeffit/ifeffit/main.log for details.

[maxwilke]

main.log file

[ryandesign (Ryan Carsten Schmidt)]

Duplicate of #61570.