It appears that we can - theoretically - build a single static library that includes both simulator and iPhone and iPad.
However, Apple has no documentation on this
IOS 10 Update:
I had a problem with building the fatlib with iphoneos10.0 because the regular expression in the script only expects 9.x and lower and returns 0.0 for ios 10.0
to fix this just replace
SDK_VERSION=$(echo ${SDK_NAME} | grep -o '.\{3\}$')
with
SDK_VERSION=$(echo ${SDK_NAME} | grep -o '[\\.0-9]\{3,4\}$')