[J-core] nextpnr build failed with weird cmake error?

[Rob Landley]

On 9/15/20 5:36 AM, Rob Landley wrote:
> Jeff, I'm trying to add icestorm and nextpnr to the toolchain build, following
> your model, and I got:

Alas, Jeff is on a plane back to Japan (finally!) in something like 6 hours so
can't help debug this one, but he confirmed on the phone that he hasn't seen it
on a mac and two linux boxes. So...

> -- Looking for sys/types.h
> CMake Error at /usr/share/cmake-3.7/Modules/CheckIncludeFile.cmake:56 (try_compile):
>   Unknown extension ".c" for file
> 
>     /home/landley/yogh2/sub2/nextpnr/CMakeFiles/CMakeTmp/CheckIncludeFile.c
> 
>   try_compile() works only for enabled languages.  Currently these are:
> 
>     CXX
> 
> Does this sound familiar? (This is _after_ I installed
> libboost{,thread,system,iostreams,rogram-options,filesystem}-dev libeigen3-dev
> for this monster...)
> 
> It's using more or less your build invocation:
> 
> cd nextpnr &&
> cmake . -DARCH="ice40" -DCMAKE_INSTALL_PREFIX="$PREFIX" \
>   -DICESTORM_INSTALL_PREFIX="$PREFIX" -DBUILD_GUI=OFF -DBUILD_PYTHON=OFF \
>   -DSTATIC_BUILD=ON &&
> make -j $(nproc) &&
> cd .. || exit 1

According to http://www.grokit.ca/cnt/CMakeProblemsSolutions/ the fix is to add
ENABLE_LANGUAGE(C) to the CMakeLists.txt file (if your system's cmake install
doesn't have that installed in the global overrides). The problem is there isn't
one. Or more accurately, there isn't JUST one:

  $ find nextpnr -name CMakeLists.txt | wc -l
  32

Ok, cmake man page... let's try adding -P<(echo "ENABLE_LANGUAGE(C)") and:

  CMake Error: Error processing file: -DARCH=ice40

Really? REALLY? The cmake command line parser can't understand -PFILE it needs
-P FILE with a space? Yes, that would appear to be the case...

CMake Error at /dev/fd/63:1 (ABLE_LANGUAGE):
  Unknown CMake command "ABLE_LANGUAGE".

And it wants a seekable file, because of course it does...

CMake Error at /dev/fd/63:1 (ENABLE_LANGUAGE):
  Command enable_language() is not scriptable

Sigh. Ok, digging back... I need to add C to the project() language list at the
top level, and it should get inherited? Ok, that built.

I should submit a pull request...

Rob