The error message indicates that the configure script cannot locate the header file argtable2.h, which is part of the argtable2 library required by Clustal Omega.

To resolve this on your M1 MacBook, install the argtable2 library using Homebrew, as it handles dependencies correctly for the arm64 architecture.

If Homebrew is not installed, execute this command in the Terminal:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

Next, install argtable2 with this command:

brew install argtable

Navigate to your Clustal Omega source directory and run the configure command with the appropriate flags to point to Homebrew's installation paths:

./configure CFLAGS='-I/opt/homebrew/include' LDFLAGS='-L/opt/homebrew/lib'

After configuration succeeds, compile the software:

make

Install it to the default location (/usr/local/bin):

make install

If the install step requires elevated permissions, prefix it with sudo. You can now run Clustal Omega using the command clustalo.

Kevin