gcc security, bug fix, and enhancement update

[4.8.5-28.0.1]

• [Orabug: 27557686] (Egeyar Bagcioglu)
• Introduce ‘oracle_release’ into .spec file. Echo it to gcc/DEV-PHASE.
  [4.8.5-28]
• Minor testsuite fixes to clean up test results (#1469697)
• retpoline support for spectre mitigation (#1535655)
  [4.8.5-27]
• bump for rebuild with RELRO enabled even for ppc64/ppc64le
  [4.8.5-26]
• Avoid red zone probing for zero residual dynamic allocation (#1469697)
• Avoid bogus CFIs for probes in noreturn fucntions on x86/x86_64 (#1469697)
  [4.8.5-25]
• Avoid red zone probe on aarch64 (#1469697)
  [4.8.5-24]
• Sync gcc48-rh1469697-13 patch to upstream (#1469697)
• Avoid probing in the red zone for noreturn functions (#1507980, #1469697)
• Avoid infinite loop if probing interval is less than guard size (#1469697)
• Fix debug information for large probing interval on aarch64 (#1469697)
• Fix ICE on ppc port with large probing interval (#1469697)
• rebuild to remove static relocations not known to older linkers (#1508968)
  [4.8.5-23]
• rebuild to remove static relocations not known to older linkers (#1508968)
  [4.8.5-22]
• fix gcc.c-torture/execute/pr80692.x
• fix divmod expansion (PR middle-end/78416)
  [4.8.5-21]
• fix 27_io/basic_fstream/53984.cc
• fix for classes with bases with mutable members (PR c++/77375)
• fix handling side-effects of parameters (PR c/77767)
• fix combine’s make_extraction (PR rtl-optimization/78378)
• fix gimplification of const var initialization from COND_EXPR (PR c++/80129)
• fix -A / -B to A / B folding (PR middle-end/80362)
• fix comparison of decimal float zeroes (PR middle-end/80692)
• fix __mulv[dt]i3 and expand_mul_overflow (PR target/82274)
  [4.8.5-20]
• handle exceptions in basic_istream::sentry (#1469384)
• don’t run pr63354.c on ppc (#1468546)
• ensure proxy privatization safety (#1491395)
• fix incorrect codegen from rdseed intrinsic use (#1482762, CVE-2017-11671)
• on aarch64, remove libatomic.so (#1465510)
  [4.8.5-19]
• Backport stack clash protection from upstream (#1469697)
  [4.8.5-18]
• backport several -mprofile-kernel fixes (#1468546)
  [4.8.5-17]
• fix -mcpu=power8 atomic expansion (#1437220, PR target/69644)
• fix .toc alignment (#1487434)