Generate configure-macros

[kddnewton]

Fixes #1041

We now use a configure-macros.in file that generates a configure-macros text file containing the definitions generated by autotools. On my machine that means:

-DPACKAGE_NAME=\"YARP\" -DPACKAGE_TARNAME=\"yarp\" -DPACKAGE_VERSION=\"0.4.0\" -DPACKAGE_STRING=\"YARP\ 0.4.0\" -DPACKAGE_BUGREPORT=\"https://github.com/ruby/yarp/issues/new\" -DPACKAGE_URL=\"https://github.com/ruby/yarp\" -DYP_VERSION_MAJOR=0 -DYP_VERSION_MINOR=4 -DYP_VERSION_PATCH=0 -D_XOPEN_SOURCE=700 -DHAVE_MMAP=1 -DHAVE_STRNCASECMP=1

You can get this by running autoconf && ./configure.

This PR also centralizes some stuff around versioning. For example we now reference PACKAGE_VERSION to try to minimize the places we're stating the version numbers.

[eregon]

I'll take a look next week how we can use this in TruffleRuby's build process.

[eregon]

This is turning out to be quite difficult from a quick look.
Currently, TruffleRuby only imports include/ and src/ (and java/): https://github.com/oracle/truffleruby/blob/master/tool/import-yarp.sh
And mx generates a ninja file to compile everything, and also compile the yarp_bindings.c JNI file all as one .so.

But the autotools stuff is at the root, so it won't be copied and there is no way to run in the TruffleRuby repo while only importing those. We could import more, but it starts to feel more brittle. We could import the whole repo, but that seems a lot of stuff not needed.
I suppose we could import configure* or so, and hope that doesn't need other files.

[eregon]

Generating a header seems nicer and more consistent, I tried that in #1088

[eregon]

#1088 works so I'll close this.
TruffleRuby can now use YARP's Makefile, use the static library, and then creates a dynamic library with the JNI bindings + librubyparser.a: oracle/truffleruby#3140