[MacPorts] #60246: git 2.25.1_0 +credential_osxkeychain +diff_highlight +doc +pcre +perl5_28]: fails to install, 'unistd.h' file not found

[MacPorts]

#60246: git 2.25.1_0 +credential_osxkeychain +diff_highlight +doc +pcre +perl5_28]:
fails to install, 'unistd.h' file not found
-------------------------+--------------------
 Reporter:  jlargentaye  |      Owner:  (none)
     Type:  defect       |     Status:  new
 Priority:  Normal       |  Milestone:
Component:  ports        |    Version:
 Keywords:               |       Port:  git
-------------------------+--------------------
 Upgrading Git on Cataline 15.3, with a developer seed of XCode 12 &
 associated CommandLineTools.

 Of note in the logs:
 - include paths used at compile time, {{{/opt/local/include}}} and
 {{{/usr/local/include}}}, indeed do not contain the header file unistd.h
 - {{{DEVELOPER_DIR}}} is reported to be
 {{{DEVELOPER_DIR='/Library/Developer/CommandLineTools'}}} even though, in
 my environment, it is set to
 {{{/Applications/Xcode.app/Contents/Developer}}}, and the output of
 {{{xcode-select -p}}} is also
 {/Applications/Xcode.app/Contents/Developer}}} (and the path exists)

 Additionally, unistd.h exists at various locations in SDKs under
 {{{/Library/Developer/CommandLineTools}}} and
 {{{/Applications/Xcode.app/Contents/Developer}}}. Specific paths can be
 provided on request.

-- 
Ticket URL: <https://trac.macports.org/ticket/60246>
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