[jdk11u-dev] RFR: 8217233: Update build settings for AIX/xlc [v2]

[Tyler Steele]

> Discovered while bringing xlc 16.1 support to jdk11. This change adds stack protection to AIX and cleans up the flags to apply #998.
> 
> Reviewed-by: clanger, sgroeger
> 
> Backport Conflicts:
> - minor conflict in flags-cflags.m4 (potentially caused by comment
> addition?)

Tyler Steele has updated the pull request incrementally with one additional commit since the last revision:

  Remove comment picked up from backport

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk11u-dev/pull/1030/files
  - new: https://git.openjdk.java.net/jdk11u-dev/pull/1030/files/3509aa66..44aa520f

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=1030&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=1030&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/1030.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/1030/head:pull/1030

PR: https://git.openjdk.java.net/jdk11u-dev/pull/1030