Add standalone build, remove VS dependency

.gitignore

@@ -1,11 +1,11 @@
-# Downloaded installers
-installers/
+# Downloaded files
+downloads/
 
 # Generated NSIS scripts
 *.nsi
 
 # Built installers
 bin/
 
-# Build tools
+# Builds/staging
 build/

build-picotool.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+
+set -euo pipefail
+
+BITNESS=$1
+ARCH=$2
+
+export PICO_SDK_PATH="$PWD/pico-sdk"
+export LIBUSB_ROOT="/mingw$BITNESS"
+export LDFLAGS="-static -static-libgcc -static-libstdc++"
+
+cd pico-sdk/tools/elf2uf2
+mkdir -p build
+cd build
+cmake -G Ninja .. -DCMAKE_BUILD_TYPE=Release -Wno-dev
+cmake --build .
+
+cd ../../pioasm
+mkdir -p build
+cd build
+cmake -G Ninja .. -DCMAKE_BUILD_TYPE=Release -Wno-dev
+cmake --build .
+
+cd ../../../..
+INSTALLDIR="pico-sdk-tools/mingw$BITNESS"
+mkdir -p $INSTALLDIR
+cp pico-sdk/tools/elf2uf2/build/elf2uf2.exe $INSTALLDIR
+cp pico-sdk/tools/pioasm/build/pioasm.exe $INSTALLDIR
+cp ../packages/pico-sdk-tools/pico-sdk-tools-config.cmake $INSTALLDIR
+
+cd picotool
+mkdir -p build
+cd build
+cmake -G Ninja .. -DCMAKE_BUILD_TYPE=Release
+cmake --build .
+
+cd ../..
+INSTALLDIR="picotool-install/mingw$BITNESS"
+mkdir -p $INSTALLDIR
+cp picotool/build/picotool.exe $INSTALLDIR
+cp "/mingw$BITNESS/bin/libusb-1.0.dll" $INSTALLDIR