message: build: bump gperftools version
  Use version
  (2.8rc), which includes commit
  which fixes segmentation faults on s390x.
diff: @@ -102,11 +102,11 @@ REPOSITORY_LOCATIONS = dict(
  ),
  com_github_gperftools_gperftools = dict(
  # TODO(cmluciano): Bump to release 2.8
  - # This sha is specifically chosen to fix ppc64le builds that require inclusion
  - # of asm/ptrace.h
  - sha256 = "18574813a062eee487bc1b761e8024a346075a7cb93da19607af362dc09565ef",
  - strip_prefix = "gperftools-fc00474ddc21fff618fc3f009b46590e241e425e",
  - urls = ["https://github.com/gperftools/gperftools/archive/fc00474ddc21fff618fc3f009b46590e241e425e.tar.gz"],
  + # The currently used version is specifically chosen to fix ppc64le builds that require inclusion
  + # of asm/ptrace.h, and also s390x builds that require special handling of mmap syscall.
  + sha256 = "97f0bc2b389c29305f5d1d8cc4d95e9212c33b55827ae65476fc761d78e3ec5d",
  + strip_prefix = "gperftools-gperftools-2.7.90",
  + urls = ["https://github.com/gperftools/gperftools/archive/gperftools-2.7.90.tar.gz"],
  ),
  com_github_grpc_grpc = dict(
  # TODO(JimmyCYJ): Bump to release 1.27
  