Recently I was working on a project with multiple Makefiles, ie Makefile.{win,nix}. My Emacs config did not load makefile-mode due to the suffixes. As spaces are my default, I got spaces on TAB, iirc even after turning on makefile-mode.
Whoever is responsible should rename the files so their names end with ".mk" or ".make", the standard extensions that Emacs and other editors recognize.
Auto-detecting tabs/spaces sounds like magic, which not everyone likes.
Not sure who you're responding to. I don't blame anything here, just illustrate what might cause confusion of tabs and spaces in Makefiles, namely unexpected filename suffixes. Holds true for other editors besides Emacs obviously.
Recently I was working on a project with multiple Makefiles, ie Makefile.{win,nix}. My Emacs config did not load makefile-mode due to the suffixes. As spaces are my default, I got spaces on TAB, iirc even after turning on makefile-mode.