Build support for Microsoft Windows.

lib/bin/build_lib

@@ -53,7 +53,13 @@ _initialize() {
 # By default, this will check for `automake` and `autoreconf`.
 initialize_needs() { _initialize_needs "$@"; }
 _initialize_needs() {
-    needs automake autoreconf
+    if [[ $platform = windows ]]; then
+        needs cmd
+        export VSINSTALLDIR="${VSINSTALLDIR:-$(cd "$(cygpath -F 0x002a)/Microsoft Visual Studio"/*/*/Common7/.. && pwd)}"
+        [[ -e "$VSINSTALLDIR/Common7/Tools/VsMSBuildCmd.bat" ]] || { echo >&2 "Missing: msbuild.  Please install 'Build Tools for Visual Studio'."; return 1; }
+    else
+        needs automake autoreconf
+    fi
 }
 
 # clean <prefix> <platform>
@@ -64,6 +70,13 @@ _initialize_needs() {
 clean() { _clean "$@"; }
 _clean() {
     rm -rf "$prefix"
+
+    if [[ $platform = windows ]]; then
+        printf '"%%VSINSTALLDIR%%\Common7\Tools\VsMSBuildCmd.bat" && msbuild /t:Clean' > .clean.bat
+        cmd //c .clean.bat
+        rm -f .clean.bat
+    fi
+
     [[ ! -e Makefile ]] || make -s distclean
     [[ ! -e .git ]] || git clean -fdx
 }
@@ -103,6 +116,8 @@ prepare_config() { _prepare_config "$@"; }
 _prepare_config() {
     local prefix=$1 platform=$2; shift 2
 
+    [[ $platform = windows ]] && return
+
     [[ -e configure ]] || autoreconf --verbose --install --symlink 2> >(sed 's/^\([^:]*\):[0-9]\{1,\}: /\1: /')
 }
 
@@ -127,6 +142,8 @@ target_prepare() { _target_prepare "$@"; }
 _target_prepare() {
     local prefix=$1 platform=$2 arch=$3; shift 3
 
+    [[ $platform = windows ]] && return
+
     [[ ! -e Makefile ]] || make -s clean
 }
 
@@ -140,6 +157,9 @@ _target_configure() {
     local prefix=$1 platform=$2 arch=$3; shift 3
 
     case "$platform" in
+        'windows')
+            return
+        ;;
         'android')
             host=( "$SDKROOT"/*-android* ) host=${host##*/}
 
@@ -164,10 +184,16 @@ _target_configure() {
 target_build() { _target_build "$@"; }
 _target_build() {
     local prefix=$1 platform=$2 arch=$3; shift 3
-    #make -j3 check
 
-    cores=$(getconf NPROCESSORS_ONLN 2>/dev/null || getconf _NPROCESSORS_ONLN 2>/dev/null ||:)
-    make -j"${cores:-3}" install
+    if [[ $platform = windows ]]; then
+        # I cannot for the life of me figure out how to pass this command directly into cmd.
+        printf '"%%VSINSTALLDIR%%\Common7\Tools\VsMSBuildCmd.bat" && msbuild /t:Rebuild /p:Configuration=ReleaseDLL;Platform=%s;OutDir=%s' "$arch" "$(cygpath -w "${prefix##$PWD/}/$arch/")" > .build.bat
+        cmd //c .build.bat
+        rm -f .build.bat
+    else
+        local cores=$(getconf NPROCESSORS_ONLN 2>/dev/null || getconf _NPROCESSORS_ONLN 2>/dev/null ||:)
+        make -j"${cores:-3}" install
+    fi
 }
 
 # finalize <prefix> <platform> [ <arch> ... ]
@@ -189,10 +215,16 @@ finalize_merge() { _finalize_merge "$@"; }
 _finalize_merge() {
     local prefix=$1 platform=$2; shift 2
 
-    mv -f -- "$prefix/$1/include" "$prefix/out/"
+    [[ -e "$prefix/$1/include" ]] && mv -f -- "$prefix/$1/include" "$prefix/out/"
 
     mkdir -p "$prefix/out/lib"
     case "$platform" in
+        'windows')
+            for arch; do
+                install -d "$prefix/out/lib/$arch"
+                install -p "$prefix/Win32/"*.lib "$prefix/out/lib/"
+            done
+        ;;
         'macos'|'ios')
             for lib in "$prefix/$1/lib/"*; do
                 if lipo -info "$lib" >/dev/null 2>&1; then
@@ -247,6 +279,7 @@ _build() {
             'macos') archs=( 'x86_64' ) ;;
             'ios') archs=( 'i386' 'x86_64' 'armv7' 'armv7s' 'arm64' ) ;;
             'android') archs=( 'arm' 'arm64' 'x86' 'x86_64' ) ;;
+            'windows') archs=( 'Win32' 'x64' ) ;;
         esac
     fi
 
@@ -270,6 +303,8 @@ _build() {
 
         # Set up a base environment for the platform.
         case "$platform" in
+            'windows')
+            ;;
             'macos')
                 SDKROOT="$(xcrun --show-sdk-path --sdk macosx)"
                 export PATH="$(xcrun --show-sdk-platform-path --sdk macosx)/usr/bin:$PATH"