ERROR: Could not find a suitable GCC

[jbrea]

I tried to install Knet on a Ubuntu 18.04 server and ran into this issue, which I now think is caused by an error of CUDAapi to find a suitable GCC

julia> using CUDAapi

julia> tk = CUDAapi.find_toolkit()
1-element Array{String,1}:
 "/usr/local/cuda-9.0"

julia> tc = CUDAapi.find_toolchain(tk)
ERROR: Could not find a suitable GCC
Stacktrace:
 [1] error(::String) at ./error.jl:33
 [2] macro expansion at ./logging.jl:313 [inlined]
 [3] find_host_compiler(::VersionNumber) at /root/.julia/packages/CUDAapi/mUc5V/src/discovery.jl:359
 [4] find_toolchain(::Array{String,1}, ::VersionNumber) at /root/.julia/packages/CUDAapi/mUc5V/src/discovery.jl:494
 [5] find_toolchain(::Array{String,1}) at /root/.julia/packages/CUDAapi/mUc5V/src/discovery.jl:487
 [6] top-level scope at none:0

julia> CUDAapi.find_host_compiler()
("/usr/bin/gcc", v"7.3.0")

(v0.7) pkg> status
    Status `~/.julia/environments/v0.7/Project.toml`
  [3895d2a7] CUDAapi v0.5.0+ #master (https://github.com/JuliaGPU/CUDAapi.jl.git)

julia> versioninfo()
Julia Version 0.7.0
Commit a4cb80f3ed (2018-08-08 06:46 UTC)
Platform Info:
  OS: Linux (x86_64-linux-gnu)
  CPU: Intel(R) Xeon(R) CPU E5-2680 v3 @ 2.50GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-6.0.0 (ORCJIT, haswell)

In the shell I get

nvcc --version
nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2017 NVIDIA Corporation
Built on Fri_Sep__1_21:08:03_CDT_2017
Cuda compilation tools, release 9.0, V9.0.176

and

gcc --version
gcc (Ubuntu 7.3.0-16ubuntu3) 7.3.0
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[maleadt]

CUDA 9.0 requires GCC < 7.

[maleadt]

I'll add some warning messages to CUDAapi to make this clear.

[maleadt]

7835f7b

[jbrea]

Thanks!