Add a script to update the library and subset it

Author: ldionne

third-party/update_boost_math.sh

@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+
+set -e # stop at the first error
+
+SCRIPT_DIR=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" &> /dev/null && pwd)
+
+echo "This script deletes ${SCRIPT_DIR}/boost-math and re-downloads it from the standalone Boost.Math release."
+echo "It then subsets it so it only contains the parts that are used in libc++."
+echo
+read -p "To continue, please enter the version you wish to download (e.g. 1.89.0), or Ctrl+C to cancel: " version
+
+# Boost versions are always 1.xx.yy so far, use this to validate.
+# That will probably have to be updated at some point.
+if [[ "${version}" != "1."* ]]; then
+    echo "Invalid version '${version}' provided, was expecting 1.XX.YY"
+    exit 1
+fi
+
+echo "****************************************"
+echo "Downloading Boost.Math ${version}"
+echo "****************************************"
+BOOST_URL="https://github.com/boostorg/math/archive/refs/tags/boost-${version}.tar.gz"
+function cleanup_tarball() {
+    rm ${SCRIPT_DIR}/boost-math-${version}.tar.gz
+}
+trap cleanup_tarball EXIT
+wget "${BOOST_URL}" -O ${SCRIPT_DIR}/boost-math-${version}.tar.gz
+rm -rf ${SCRIPT_DIR}/boost-math
+mkdir ${SCRIPT_DIR}/boost-math
+tar -x --file ${SCRIPT_DIR}/boost-math-${version}.tar.gz -C ${SCRIPT_DIR}/boost-math --strip-components=1
+
+echo "****************************************"
+echo "Subsetting Boost.Math ${version}"
+echo "****************************************"
+rm -rf ${SCRIPT_DIR}/boost-math/{.circleci,.drone,.github,build,config,doc,example,meta,test,tools}