I created a new project using Alire for the ARM cortex. By default, the gprconfig assumes you're building a native library if you don't explicitly specify the target and runtime in your project file. I forgot to specify them and got the following errors even though I added ARM libraries to the project and selected the arm toolchain using ALIRE.

gprconfig: can't find a native toolchain for language 'asm_cpp'
gprconfig: can't find a native toolchain for language 'ada'
gprconfig: can't find a native toolchain for language 'asm_cpp'
gprconfig: can't find a native toolchain for language 'ada'

This error was difficult to solve because I presumed gprconfig found the arm toolchain, but couldn't find the native compiler it needed for some utility reason. Eventually, I compared my project file with another Ada project and discovered the target and runtime wasn't configured., leading to the error.

This is a common error found on forums and given how often Ada is used for cross compilation, it would be very useful if the error message suggested checking if target and runtime are correctly set, or warn the user after selecting a toolchain if the target and runtime are compatible with the specified or default target and runtime. It raises a question about whether it fits within ALIRE scope of responsibilities. It could be argued it is since ALIRE is responsible for selecting the project's toolchain.