* img2sixel.c: Use gdk-pixbuf and libcurl.
* build-gdkpixbuf.sh: Added.
this commit is imported from arakiken/libsixel.
https://bitbucket.org/arakiken/libsixel/commits/fda0bcab1ec2598bada3d102d8f0cf35d848f6ff
Merge branch 'arakiken-sandbox' into sandbox
Minor fix
Minor fix
Integrate libcurl only if gdk-pixbuf is not available
Check gdk-pixbuf2 and libcurl availability
Update CFLAGS and LDADD for img2sixel
Merge branch 'configure-gdkpixbuf' into arakiken-sandbox
Merge branch 'configure-gdkpixbuf' into sandbox
Minor fix
Drop build-gdkpixbuf.sh
Merge branch 'sandbox' into configure-gdkpixbuf
Add new configure options, --enable-gdk-pixbuf2 and --enable-libcurl
Minor fix
Merge branch 'configure-gdkpixbuf' into arakiken-sandbox
Merge branch 'sandbox' into arakiken-sandbox
Merge branch 'arakiken-sandbox' into travis
Update .travis.yml
Raise errors if gdk-pixbuf/libcurl are not available when they are enabled
Merge branch 'configure-gdkpixbuf' into arakiken-sandbox