Tutorial 5 improvements

[winstliu]

I've attempted to clean up tutorial 5, Makefiles, a bit.

• Removed suffix rules
  • GNU Make already supports .cpp -> .o: https://www.gnu.org/software/make/manual/html_node/Catalogue-of-Rules.html
  • Additionally, suffixes are deprecated: https://www.gnu.org/software/make/manual/html_node/Suffix-Rules.html
  • This simplifies the Makefile implementation and removes the knowledge burden of having to define something without really knowing why.
• Consistently use tabs for indentation
  • Not only does this allow for copy/pasting, but it should also prevent emacs/vim/whatever from detecting the Makefile as using spaces for indentation.
• Move -o flag to the end of the compilation command
  • We constantly see people who remove only the filename after the -o but not the flag itself, causing them to overwrite their own files. Moving it to the end should help with that.
• Simplify macros section
  • There is no need for students to know about e.g. PC or RM, and just confuses them more
  • Get rid of defaults, especially because they were wrong and because it's a potential source of confusion ("why do I have to define CXX=clang++ when the tutorial already says it's the default?").
  • Go directly into an example to show how macros are defined and used, rather than trying to be abstract at first.
• Fixes a typo in the dependencies section where targets was used instead of dependencies
  • I doubt many people make it this far, but it still should be fixed.
• Give an example of a comment in the Makefile
  • Saw a few people who forgot that Makefiles used # and were trying to use C-style comments.

Even after these changes the tutorial still seems pretty overly verbose, but it's a start, at least.

[aaronbloomfield]

Thanks!