[MacPorts] #61488: multiple ports: review macOS version checking

[MacPorts]

#61488: multiple ports: review macOS version checking
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  Reporter:  jmroot                              |      Owner:  (none)
      Type:  defect                              |     Status:  new
  Priority:  Normal                              |  Milestone:
 Component:  ports                               |    Version:
Resolution:                                      |   Keywords:
      Port:  icu-le-hb libassuan libgcrypt isl   |
  libdaemon cloog gdbm db60 db48 net-snmp hdf4   |
  gsl gcc46 gcc48 gcc49 gcc47 gcc45 gcc44        |
  libcanberra sox xorg-libXxf86vm libart_lgpl    |
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Comment (by ryandesign):

 As is the case anytime you patch a port that uses autotools, you should
 only patch generated files or only patch non-generated files, not both. If
 your port does not run auto(re)conf, patch the generated configure file.
 If your port runs auto(re)conf and has a libtool.m4, patch that. If your
 port runs auto(re)conf and does not have a libtool.m4, patch nothing; the
 patched libtool.m4 from the libtool port will be used. If you patch both
 but do not run auto(re)conf, make absolutely certain that your patch for
 configure is performed after the patches for the m4 files, otherwise
 depending on timing sometimes it will cause configure to be regenerated
 when you did not want it to be.

 The libtool port patches both because it needs to both have a fixed
 configure script at build time and it needs to install a patched
 libtool.m4 for others to use.

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Ticket URL: <https://trac.macports.org/ticket/61488#comment:5>
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