This change adds the ability to produce host static build for the
libdouble-conversion library. Other host build tools can now depend on
this library if they need it.

Tested on a x86_64 host build machine.
make package/libdouble-conversion/host/compile produces
staging_dir/hostpkg/lib/libdouble-conversion.a file

Signed-off-by: Amol Bhave <ambhave@fb.com>

Added patch to fix compilation on big endian ARM.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

Switched to codeload and updated the Makefile to standards.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

fix Makefile chmod (644)
replace MD5SUM with HASH
add PKG_MIRROR_HASH when PKG_SOURCE_PROTO:=git

(PKG_SOURCE_PROTO:=svn tarballs are not reproducible for now)

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>