PSA: GNU gdb & binutils prebuilt for diagnostic use

[Roland McGrath]

Good news, everyone!

Your Fuchsia checkout includes some new prebuilt GNU tools for development use.  These are not used in any way by the Fuchsia build and are only provided for debugging purposes.

The new fx gdb and fx gnu commands give convenient access to these tools, which are installed in //prebuilt/third_party/binutils-gdb/${PLATFORM}/bin.  Binaries are available for the same Linux and Mac platforms as other prebuilt build tools.

We primarily use static linking for our host tools to keep the prebuilt binaries compatible with a wide variety of OS installations.  However, this is not possible with some support libraries used by GDB.  On Linux, you may need to run sudo apt install libpython3.7 libdebuginfod1 or your distro's equivalent before using some of these tools.

This is a build of the upstream GNU tools from the trunk of the binutils-gdb repo.  https://ci.chromium.org/p/fuchsia/g/binutils/ tracks the bots building the packages.  New builds will be rolled into Fuchsia periodically.

If you use the GNU tools such as gdb (or gdb-multiarch) or objdump from your Linux installation, these versions will likely work better.

Please note the Fuchsia Toolchain team can provide only best-effort assistance and support for these tools.  The LLVM tools provided in the clang prebuilt are the primary tools supported by the team and used in the build process.

Enjoy!