[MacPorts] #57743: db48 +java build fails on MacOS 10.14.1

[MacPorts]

#57743: db48 +java build fails on MacOS 10.14.1
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  Reporter:  russhousley  |      Owner:  jmroot
      Type:  defect       |     Status:  assigned
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:  2.5.4
Resolution:               |   Keywords:
      Port:  db48         |
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Comment (by sharris40):

 There are actually four separate problems here:
  1. java_home isn't properly checked.
  2. The scripts assume the include subdirectory is genunix, not darwin.
  3. Version detection is broken (because of course it is).
  4. The class files ''must'' be built for Java 7 or earlier.

 Issues 1-3 are simple patches to dist/configure. Issue 4 can be solved by
 cross-compiling. While we ''can'' just set source and target in
 JAVACFLAGS, we really should have an rt.jar from Java 7. It would probably
 be best to add a new port that downloads the Java 7 reference
 implementation from java.net and extracts the architecture-independent
 library files somewhere in the prefix, add that port as a build dependency
 to the java variant, and set the bootclasspath to that rt.jar along with
 setting source and target to 1.7.

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Ticket URL: <https://trac.macports.org/ticket/57743#comment:5>
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