Add root .gitignore

This project uses autotools which generates many files not kept in git. This
commit adds files generated by:
./bootstrap
./configure

Signed-off-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Samuel Mendoza-Jonas <sam@mendozajonas.com>

.gitignore

@@ -0,0 +1,20 @@
+ABOUT-NLS
+Makefile.in
+aclocal.m4
+autom4te.cache/*
+compile
+config.guess
+config.h.in
+config.log
+config.rpath
+config.sub
+configure
+cscope.out
+depcomp
+install-sh
+ltmain.sh
+m4/*
+missing
+po/*
+test-driver
+ylwrap