* autogen.sh: add more portable #!, provide -e key explicitly
This is minority, NixOS and some other distros do not have this `sh`,
paradoxically `/usr/bin/env` path is more widespread.
Also documenting `set -e`
* autogen.sh: upd output, make it portable
`echo` has different behaviour, keys and possibilities on different systems.
Example:
```
echo "Line1\nLine2"
```
Is probably parses `\n` in `macOS`, while Linux `echo` didn't, resulting
in verbatim line.
`printf` special character parsing is much more portable.
Also removed the thanks "You followed directions! Great work!"
to the person that just ran one command, which is a script that has one command
inside and thanks the person for that.
* remove c3d/build
* autotools start
* ignore
* autoreconf? idk
* linux/osx gcc/clang
* no glut, need glew tho
* fix test matrix
* fix linux conditional includes?
* sdl makefile am
* SDL2 m4/autoconf
* idk more m4 crap
* ignore more junk
* ug
* go away idk
* renderer makefile
* fixing SDL's broken-ass sdl2.m4 lol
* progress
* cmake go away
* full autotools build working yay
* autogen script, readme update
* fix linux ifdefs
* stuff
* fix linux -ldl
* mac sdl dep for travis
* whoops
* brewwww
* no osx gcc
* no test
* kinda working linux library build
* travis apt packages
* ignore old SDL2 for travis
* typo
* autogen for osx build readme
