refactor(mk): move build rules into separate scripts (#855)

See https://github.com/ooni/probe/issues/2218

MOBILE/ios/check-xcode-version

@@ -0,0 +1,19 @@
+#!/bin/bash
+
+set -euo pipefail
+
+EXPECTED_XCODE_VERSION=${EXPECTED_XCODE_VERSION:-13.4.1}
+
+printf "checking for xcodebuild... "
+command -v xcodebuild || {
+	echo "not found"
+	exit 1
+}
+
+printf "checking for Xcode version... "
+__XCODEVERSION_REAL=$(xcodebuild -version | grep ^Xcode | awk '{print $2}')
+echo $__XCODEVERSION_REAL
+[[ "$EXPECTED_XCODE_VERSION" = "$__XCODEVERSION_REAL" ]] || {
+	echo "fatal: Xcode version must be $EXPECTED_XCODE_VERSION instead of $__XCODEVERSION_REAL"
+	exit 1
+}

MOBILE/ios/createpodspec

@@ -0,0 +1,6 @@
+#!/bin/bash
+set -euo pipefail
+__version=$(date -u +%Y.%m.%d-%H%M%S)
+__release=$(git describe --tags || echo '0.0.0-dev')
+cat ./MOBILE/ios/template.podspec | sed -e "s/@VERSION@/$__version/g" \
+	-e "s/@RELEASE@/$__release/g" >./MOBILE/ios/oonimkall.podspec

MOBILE/ios/zipframework

@@ -0,0 +1,7 @@
+#!/bin/bash
+set -euxo pipefail
+(
+	cd ./MOBILE/ios
+	rm -rf oonimkall.xcframework.zip
+	zip -yr oonimkall.xcframework.zip oonimkall.xcframework
+)