RFR: 8298006: Build failure by maybe-uninitialized error on Linux s390x GCC8

[Ichiroh Takiguchi]

I changed GCC toolchain from GCC6 to GCC8 on SLES12SP5 Linux s390x.
I could see following errors:

src/java.desktop/share/native/libawt/awt/medialib/awt_ImagingLib.c: In function 'allocateRasterArray':
src/java.desktop/share/native/libawt/awt/medialib/awt_ImagingLib.c:2944:73: error: 'roff[3]' may be used uninitialized in this function [-Werror=maybe-uninitialized]
                             (((*inP&rasterP->sppsm.maskArray[c]) >> roff[c])
                                                                     ~~~~^~~


According to error messages,
roff and loff may not be initialized.

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

Commit messages:
 - 8298006: Build failure by maybe-uninitialized error on Linux s390x GCC8

Changes: https://git.openjdk.org/jdk/pull/11475/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11475&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8298006
  Stats: 61 lines in 1 file changed: 60 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/11475.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11475/head:pull/11475

PR: https://git.openjdk.org/jdk/pull/11475