- cmake/GetSNAP.cmake: add include directory flag for SNAP CXXFLAGS.
- list of flags to split over multiple lines and then join into one string.

Signed-off-by: Aiden Woodruff <woodra@rpi.edu>

- cmake/GetSNAP.cmake: only build the SNAP library; saves a minute of building
	examples.
- cmake/snap-glib.patch: rename from snap-glib-base.patch since fl.cpp is also
	being patched.

Signed-off-by: Aiden Woodruff <woodra@rpi.edu>

- cmake/GetSNAP.cmake: check for poll.h or sys/poll.h.
- combine SNAP flags into one variable.
- add downstream SNAP flags to CMake target interface.
- cmake/snap-glib-base.patch: add conditional <poll.h> inclusion.

Signed-off-by: Aiden Woodruff <woodra@rpi.edu>

- cmake/GetSNAP.cmake: run patch or git apply to add fixes to glib-core when
	compiling with musl (i.e. POSIX).
- check wordsize with `sizeof(void*)` (from cmake) and inject into SNAP with
	the patch step
- add BUILD_BYPRODUCT so that ninja works.
- add directories to ensure include/link commands don't error
- cmake/snap-glib-base.patch: add fix for the word size.
- add fix for how they do environ
- fix single quotes in write function

Signed-off-by: Aiden Woodruff <woodra@rpi.edu>

Signed-off-by: Aiden Woodruff <woodra@rpi.edu>

- cmake/GetSNAP.cmake: add include directory to imported target.
- src/main.cc: include SNAP and simple graph.

Signed-off-by: Aiden Woodruff <woodra@rpi.edu>

- cmake/GetSNAP.cmake: add module that uses ExternalProject to download and
	build (with make) the SNAP library.
- CMakeLists.txt: simple cmake file to use the GetSNAP module.
- src/main.cc: simples possible main file.
- src/CMakeLists.txt: simple cmake file with main executable and linking.

Signed-off-by: Aiden Woodruff <woodra@rpi.edu>