build: create a standalone build script for libsecp256k1

heavily based on Electron-Cash/Electron-Cash@eda015908e

contrib/osx/make_osx

@@ -7,6 +7,8 @@ PACKAGE=Electrum
 GIT_REPO=https://github.com/spesmilo/electrum
 LIBSECP_VERSION="b408c6a8b287003d1ade5709e6f7bc3c7f1d5be7"
 
+export GCC_STRIP_BINARIES="1"
+
 . $(dirname "$0")/base.sh
 
 CONTRIB_OSX="$(dirname "$(realpath "$0")")"
@@ -16,7 +18,6 @@ ROOT_FOLDER="$CONTRIB/.."
 src_dir=$(dirname "$0")
 cd $src_dir/../..
 
-export PYTHONHASHSEED=22
 VERSION=`git describe --tags --dirty --always`
 
 which brew > /dev/null 2>&1 || fail "Please install brew from https://brew.sh/ to continue"
@@ -96,17 +97,10 @@ cp $BUILDDIR/libusb/1.0.22/lib/libusb-1.0.dylib contrib/osx
 echo "82c368dfd4da017ceb32b12ca885576f325503428a4966cc09302cbd62702493  contrib/osx/libusb-1.0.dylib" | \
     shasum -a 256 -c || fail "libusb checksum mismatched"
 
-info "Building libsecp256k1"
+info "Preparing for building libsecp256k1"
 brew install autoconf automake libtool
-git clone https://github.com/bitcoin-core/secp256k1 $BUILDDIR/secp256k1
-pushd $BUILDDIR/secp256k1
-git reset --hard $LIBSECP_VERSION
-git clean -f -x -q
-./autogen.sh
-./configure --enable-module-recovery --enable-experimental --enable-module-ecdh --disable-jni
-make -j4
-popd
-cp $BUILDDIR/secp256k1/.libs/libsecp256k1.0.dylib contrib/osx
+"$CONTRIB"/make_libsecp256k1.sh || fail "Could not build libsecp"
+cp "$ROOT_FOLDER"/electrum/libsecp256k1.0.dylib contrib/osx
 
 info "Building CalinsQRReader..."
 d=contrib/osx/CalinsQRReader