add pffft

pffft/cross_build_mingw64.sh

@@ -0,0 +1,25 @@
+#!/bin/bash
+
+# requires debian/ubuntu packages: zip gcc-mingw-w64
+
+if [ -z "$1" ]; then
+  echo "usage: $0 <zip-post> <any other cmake options>"
+  exit 1
+fi
+
+ZIP_POST="$1"
+shift
+
+# CROSS="x86_64-w64-mingw32"
+WN="w64"
+TOOLCHAIN="mingw-w64-x64_64.cmake"
+
+rm -rf build_${WN}_${ZIP_POST}
+echo -e "\n\n********************************************************"
+echo "start build of pffft_${WN}_${ZIP_POST}"
+mkdir build_${WN}_${ZIP_POST} && \
+cmake -S . -B build_${WN}_${ZIP_POST} \
+  -DCMAKE_TOOLCHAIN_FILE=${TOOLCHAIN} \
+  -DCMAKE_INSTALL_PREFIX=pffft_bin-${WN}_${ZIP_POST} \
+  "$@" && \
+cmake --build build_${WN}_${ZIP_POST}