[MacPorts] #57990: libxml2 @2.9.7_2: ICU include directory not in pkg-config output

[MacPorts]

#57990: libxml2 @2.9.7_2: ICU include directory not in pkg-config output
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  Reporter:  dsedivec  |      Owner:  (none)
      Type:  defect    |     Status:  new
  Priority:  Normal    |  Milestone:
 Component:  ports     |    Version:  2.5.4
Resolution:            |   Keywords:
      Port:  libxml2   |
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Comment (by raimue):

 This is not about building in MacPorts (therefore no `main.log` required),
 because with MacPorts `${prefix}/include` would always be in the include
 path and this bug will not occur. This is about using libxml2 to compile
 software outside of MacPorts. The CFLAGS provided by pkg-config are
 insufficient as the `libxml/*.h` headers will try to include `unicode/*.h`
 and therefore the path to these headers also needs to be added to the pkg-
 config file.

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Ticket URL: <https://trac.macports.org/ticket/57990#comment:3>
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