RFR: 8274851: [PPC64] Port zgc to linux on ppc64le [v2]

[Niklas Radomski]

> Port the Z garbage collector ([JDK-8209683](https://bugs.openjdk.java.net/browse/JDK-8209683)) to linux on ppc64le.

Niklas Radomski has updated the pull request incrementally with two additional commits since the last revision:

 - Update autoconf error message
 - Remove copyright headers

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5842/files
  - new: https://git.openjdk.java.net/jdk/pull/5842/files/17946ddf..5da8c1b7

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5842&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5842&range=00-01

  Stats: 3 lines in 2 files changed: 0 ins; 2 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5842.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5842/head:pull/5842

PR: https://git.openjdk.java.net/jdk/pull/5842