Add lconv declaration and localeconv(3)

lconv is taken from ndk/sources/android/support/include/locale.h and
matches
bsd/glibc upstream.
Keep old declaration for 32-bits for compatibility.
localeconv.c and deps are taken from openbsd upstream.
Changed strtod.c accordingly.

Change-Id: I9fcc4d15f5674d192950d80edf26f36006cd31b4
Signed-off-by: Pavel Chupin <pavel.v.chupin@intel.com>