Hello,

I am trying to upgrade gmp to 6.0.0a, with a small added complication since
the tarball unpacks into a directory gmp-6.0.0a... The patch is attached.

The configure phase of libstdc++ now fails (config.log attached), with the
following error message:

checking for exception model to use... configure: error: unable to detect exception model

The corresponding lines in config.log seem to be the following:

x86_64-guix-linux-gnu-g++: error trying to exec 'cc1plus': execvp: No such file or directory
configure:15050: $? = 1
configure:15077: error: unable to detect exception model

Do you have an idea what is happening?

Andreas