RFR: 8374642: EscapeHash macro fails with GNU make 4.3 and 4.4

[Erik Joelsson]

The utility macro `EscapeHash` in Utils.gmk fails when running with GNU make 4.3 and 4.4. The issue seems to be fixed in 4.4.1 where it succeeds again. This failure can be observed by running the vardep tests using:


make test-make-make-base


I managed to figure out a workaround to make the macro work on these make versions, by referencing the hash character indirectly. With this fix, the test succeeds with at least GNU make 4.0, 4.2, 4.3, 4.4 and 4.4.1.

It's not clear if there is any part of the build that currently relies on this macro. This test was modified to include this check a long time ago in JDK 9 when the docs build was rewritten.

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Commit messages:
 - JDK-8374642

Changes: https://git.openjdk.org/jdk/pull/29097/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29097&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8374642
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/29097.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29097/head:pull/29097

PR: https://git.openjdk.org/jdk/pull/29097