Removing unnecessary cffi submodule

Author: Shillaker

.gitmodules

@@ -21,10 +21,6 @@
 	path = third-party/mxnet
     url = https://github.com/faasm/incubator-mxnet
     branch = faasm
-[submodule "third-party/cffi"]
-	path = third-party/cffi
-    url = https://github.com/faasm/cffi-mirror.git
-    branch = faasm
 [submodule "third-party/libffi"]
 	path = third-party/libffi
 	url = https://github.com/faasm/libffi.git

README.md

@@ -1,7 +1,7 @@
 # Faasm CPython WebAssembly build
 
 This build cross-compiles CPython and a number of Python modules to WebAssembly
-for use in [Faasm](https://github.com/lsds/faasm).
+for use in [Faasm](https://github.com/faasm/faasm).
 
 You can try to install arbitrary packages, but the ones that definitely work 
 can be listed with:
@@ -136,7 +136,7 @@ inv libs.install --experimental
 inv libs.install --name numpy
 
 # (Attempt) to install arbitrary module
-inv libs.install <module_name>
+inv libs.install --name <module_name>
 ```
 
 Libraries will then be installed to 
@@ -174,8 +174,8 @@ Then we can install mxnet and horovod:
 
 ```
 . ./cross_venv/bin/activate
-inv libs.install --name=mxnet
-inv libs.install --name=horovod
+inv libs.install --name mxnet
+inv libs.install --name horovod
 ```
 
 ### Cleaning and uninstalling 

bin/crossenv_setup.sh

@@ -45,4 +45,3 @@ echo "python3.8 is: $(which python3.8)"
 
 popd >> /dev/null
 
-

tasks/libs.py

@@ -1,24 +1,22 @@
 import os
 
 from copy import copy
+from faasmcli.util.toolchain import (
+    CMAKE_TOOLCHAIN_FILE,
+    WASM_LIB_INSTALL,
+)
 from os.path import join
 from subprocess import run
 from tasks.env import USABLE_CPUS, THIRD_PARTY_DIR, CROSSENV_DIR
 from invoke import task, Failure
 
-MXNET_LIB = "/usr/local/faasm/llvm-sysroot/lib/wasm32-wasi/libmxnet.so"
-CMAKE_TOOLCHAIN_FILE = (
-    "/usr/local/code/faasm/third-party/faasm-toolchain/WasiToolchain.cmake"
-)
+MXNET_LIB = join(WASM_LIB_INSTALL, "libmxnet.so")
 
 # Modified libs
 MODIFIED_LIBS = {
     "numpy": {
         "env": {"NPY_NUM_BUILD_JOBS": USABLE_CPUS},
     },
-    "cffi": {
-
-    },
 }
 
 MODIFIED_LIBS_EXPERIMENTAL = {