Cherry-pick 7.11 changes to 8.3

Cherry-picked commits:
c64829b: Fallback to open if multifs_open fails.
2177073: Fix gdbserver process interruption.
35ee683: Remove gdb hack.
78af0f6: Handle cross compile for locale configuration
5cbd102: Specify osabi in arm/aarch64 tdescs.
dfc5ca4: Set the default gdb osabi to GNU/Linux.

Bug: 62547070
Test: build
Change-Id: I00a97aa866255ed853c13b8f11dc1a996ea810f2
22 files changed
tree: 8e18c8939ffac06c3d86f28e32c0234c564b5a3f
  1. gdb-7.11/
  2. gdb-8.0.1/
  3. gdb-8.2/
  4. gdb-8.3/
  5. build-gdb.sh
  6. build.py