Add libopenmpt

Closes #113

scripts.d/10-mingw-std-threads.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+
+MINGW_STD_THREADS_REPO="https://github.com/meganz/mingw-std-threads.git"
+MINGW_STD_THREADS_COMMIT="f73afbe664bf3beb93a01274246de80d543adf6e"
+
+ffbuild_enabled() {
+    [[ $TARGET == win* ]] || return -1
+    return 0
+}
+
+ffbuild_dockerbuild() {
+    git-mini-clone "$MINGW_STD_THREADS_REPO" "$MINGW_STD_THREADS_COMMIT" mingw-std-threads
+    cd mingw-std-threads
+
+    mkdir -p "$FFBUILD_PREFIX"/include
+    cp *.h "$FFBUILD_PREFIX"/include
+
+    cmake -DCMAKE_TOOLCHAIN_FILE="$FFBUILD_CMAKE_TOOLCHAIN" -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX="$FFBUILD_PREFIX" \
+        -DMINGW_STDTHREADS_DIR="$FFBUILD_PREFIX"/include -DMINGW_STDTHREADS_BUILD_TEST=0 -DMINGW_STDTHREADS_GENERATE_STDHEADERS=1 .
+    cp cmake_stdheaders_generator/cmake_stdheaders_generator/* "$FFBUILD_PREFIX"/include
+}