Remove the toolchain in riscv-tools

The toolchain pointed to by riscv-tools hasn't been maintained for more
than a year now.  This pointer was necessary when we had out-of-tree
ports of the various toolchain components, but now that everything is
upstream toolchains can be obtained via dozens of standard mechanisms.
Having a broken toolchain so publicly visible causes everyone headaches,
so unless someone wants to step up and maintain this I'm going to remove
it.

In order to keep the Travis running, I've gone ahead and used
crosstool-ng to build a toolchain.  This should be a lot more reliable
than the old riscv-gnu-toolchain based approach.

1 files changed, 26 insertions, 19 deletions

diff --git a/README.md b/README.md
index 08ff1c1..7106616 100644
--- a/README.md
+++ b/README.md
@@ -1,8 +1,8 @@
 riscv-tools [![Build Status](https://travis-ci.org/riscv/riscv-tools.svg?branch=master)](https://travis-ci.org/riscv/riscv-tools)
 ===========================================================================
 
-This repository houses a set of RISC-V simulators, compilers, and other
-tools, including the following projects:
+This repository houses a set of RISC-V simulators and other tools,
+including the following projects:
 
 * [Spike](https://github.com/riscv/riscv-isa-sim/), the ISA simulator
 * [riscv-tests](https://github.com/riscv/riscv-tests/), a battery of
@@ -14,23 +14,30 @@ a boot loader for Linux and similar OS kernels, and `pk`, a proxy kernel that
 services system calls for a target-machine application by forwarding them to
 the host machine
 
-Several RISC-V tools that were previously maintained through this repository
-have since been upstreamed to their parent projects.  Although this repository
-continues to contain versions of the following tools, they are now primarily
-supported and maintained via their parent projects:
-
-* [Binutils](https://www.gnu.org/software/binutils/)
-* [GCC](https://gcc.gnu.org/), the GNU C Compiler
-* [GDB](https://www.gnu.org/software/gdb/), the GNU Debugger
-* [glibc](https://www.gnu.org/software/libc/), the GNU C Library
-* [QEMU](https://www.qemu.org/), an emulator
-* [Newlib](https://sourceware.org/newlib/), a C library
-* [OpenOCD](http://openocd.org/)
-
-Your favorite software distribution should already have packages for
-these upstream tools, but if it doesn't then the [RISC-V Port of
-OpenEmbedded](https://github.com/riscv/meta-riscv#quick-start) is a
-great place to start!
+Several RISC-V tools that were previously maintained through this
+repository have since been upstreamed to their parent projects and are
+no longer included here.  Your favorite software distribution should
+already have packages for these upstream tools, but if it doesn't then
+here are a handful of my favorites:
+
+* Your favorite software distribution may already have packages that
+  include a RISC-V cross compiler, which is probably the fastest way to
+  get started.  As of writing this README (March, 2019) I can trivially
+  find packages for ALT Linux, Arch Linux, Debian, Fedora, FreeBSD,
+  Mageia, OpenMandriva, openSUSE, and Ubuntu.
+  [pkgs.org](https://pkgs.org/) appears to be a good place to find an up
+  to date list, just search for "riscv".
+* [crosstool-ng](http://crosstool-ng.github.io/docs/) can build RISC-V
+  cross compilers of various flavors.
+* The [RISC-V Port of
+  OpenEmbedded](https://github.com/riscv/meta-riscv#quick-start)
+  builds a cross compiler, Linux kernel, and enough of userspace to do
+  many interesting things.
+* [buildroot](https://github.com/buildroot/buildroot) is a lighter
+  weight cross compiled Linux distribution.
+
+This repository uses crosstool-ng to configure a `riscv64-unknown-elf`
+toolchain.
 
 # <a name="quickstart"></a>Quickstart