RFR: JDK-8305646: compile error on Alpine with gcc12 after 8298619 in libGetXSpace.c

[Matthias Baesken]

On Alpine Linux, using gcc12, we run now into this compile warning as error :
In file included from /openjdk/linuxmuslx86_64/jdk/test/jdk/java/io/File/libGetXSpace.c:31:
/usr/include/sys/errno.h:1:2: error: #warning redirecting incorrect #include <sys/errno.h> to <errno.h> [-Werror=cpp]
    1 | #warning redirecting incorrect #include <sys/errno.h> to <errno.h>
      | ^~~~~~~
cc1: all warnings being treated as errors

We probably better just include <errno.h> like it is done at almost all other places in the codebase.

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Commit messages:
 - JDK-8305646

Changes: https://git.openjdk.org/jdk/pull/13349/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13349&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8305646
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/13349.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13349/head:pull/13349

PR: https://git.openjdk.org/jdk/pull/13349