The GCC field
A package needs a GCC field if anything in the package is compiled with c++ or g++.
How to tell if a binary has been compiled with g++
A good way to tell if a binary in your package was compiled with g++ is:
nm -g $binary > symbols c++filt3 < symbols > symbols.filt diff symbols symbols.filt
In most cases, if there is a difference it was compiled with g++ (some exceptions exist involving weirdly named C functions).
The script gcc-field can check one or more packages to see if they need a GCC field.
To check one package, run it like this:
If it prints anything, the package doesn't have the right field (or is an exceptional case). If it doesn't print anything, you're ok!
You can also check all your packages:
Or check a set of files:
find ./root-foo | gcc-field -
gcc-field --help for details.