moreutils (errno): auto-generated errno-s header file via the preprocessor

gistfile1.mak

# Taken from http://joeyh.name/code/moreutils/ Makefile
# See http://blog.liw.fi/posts/errno/ for all the details about `errno` CLI tool
errno.o: errnos.h
errnos.h:
	echo '#include <errno.h>' > dump.c
	$(CC) -E -dD dump.c | awk '/^#define E/ { printf "{\"%s\",%d},\n", $$2, $$3 }' > errnos.h
	rm -f dump.c

# On errno.c side this auto-generated header is used as follow
# --
# static struct {
#     const char *name;
#     int code;
# } errnos[] = {
#     #include "errnos.h"
# };