Unable to build `abc` on Windows: Path is too long

[xobs]

Yosys is unable to build yosys-abc on Windows because the make clean command exceeds PATH_MAX, which is 32,768 characters (see: berkeley-abc/abc#54)

When yosys is built, it clones/updates abc and then performs a make clean. Currently, this command is 55,806 characters long, and the resulting CreateProcessEx() command exits with an error.

Until that patch lands, a workaround is to manually check out abc and compile with ABCREV=default which skips this step:

git clone %ABCURL% abc
cd abc
git fetch origin master
git checkout %ABCREV%
if errorlevel 1 exit 1
cd ..
make ABCREV=default

Another option is to cross-compile on a platform with a longer PATH_MAX such as Linux, however some build systems (notably Conda) don't support cross-compiling, so this isn't always an option.