I'm looking for the way to build GRUB2 from scratch. I'm not using grub-mkimage or anything like that. I downloaded the source code with apt-get source grub2 and unzipped the Debian tarball. Inside the folder there is configure tool or autogen file. make asks me to specify a build target. Can anyone tell me how to begin with this?
If you want to compile to a .deb, have a look at this question: How do I get and modify the source code of packages installed through apt-get?
Otherwise,
./configure && make && make installis often the way to go, in the root folder of the source package.