Ensured that <stdnoreturn.h> defines a _Noreturn no-op macro when
compiling with a C99 compiler instead of a C11 compiler.
Ensured that <stdalign.h> defines the _Alignas and _Alignof no-op
macros when compiling with a C99 compiler instead of a C11 compiler.
Defined the <stdlib.h> abort(), exit(), and _Exit() functions.
Defined the <stdlib.h> quick_exit() function.
Implemented the <stdlib.h> abs(), labs(), and llabs() functions.
Defined the <stdlib.h> EXIT_FAILURE and EXIT_SUCCESS macros.
Added @see link annotations to all source files.
Defined the <string.h> strlen() and strnlen() functions.
Defined the <unistd.h> header from POSIX.1-2008.
Implemented the __sys_exit() operation for Linux (x86-64).
Implemented the most minimal crt0 for Linux (x86-64).
Implemented the most minimal possible example program.
Implemented the __sys_exit() operation for Darwin (x86-64).
Implemented the most minimal crt0 for Darwin (x86-64).
Ensured that Automake builds the correct system interface.
Ensured that the crt0.o object file gets installed.
Updated the crt0 install location in the example program Makefile.
Implemented platform support for OpenBSD (x86-64).