update SDL_mixer to SDL3_mixer 3.2.0

libs/SDL3_mixer/external/Get-GitModules.ps1

@@ -0,0 +1,41 @@
+<#
+  .SYNOPSIS
+  Downloads the Git modules specified in ../.gitmodules
+
+  .DESCRIPTION
+  Parses and downloads the Github repositories specified in the .gitmodules file
+
+  .EXAMPLE
+  PS> .\Get-GitModules.ps1
+  < Downloads and parses the repositories in the .gitmodules file. >
+#>
+
+#------- Variables -------------------------------------------------------------
+[String] $PathRegex   = "path\s*=\s*(?<path>.*)"
+[String] $URLRegex    = "url\s*=\s*(?<url>.*)" 
+[String] $BranchRegex = "branch\s*=\s*(?<Branch>.*)"
+[String[]] $Arguments = $args
+
+#------- Script ----------------------------------------------------------------
+if (-not $Arguments) {
+    [String[]]$Arguments = "--depth", "1"
+}
+
+foreach ($Line in Get-Content $PSScriptRoot\..\.gitmodules) {
+    if ($Line -match $PathRegex) {
+        $Match  = Select-String -InputObject $Line -Pattern $PathRegex
+        $Path   = $Match.Matches[0].Groups[1].Value
+    }
+    elseif ($Line -match $URLRegex) {
+        $Match  = Select-String -InputObject $Line -Pattern $URLRegex
+        $URL    = $Match.Matches[0].Groups[1].Value
+    }
+    elseif ($Line -match $BranchRegex) {
+        $Match  = Select-String -InputObject $Line -Pattern $BranchRegex
+        $Branch = $Match.Matches[0].Groups[1].Value
+        
+        Write-Host "git clone --filter=blob:none $URL $Path -b $Branch --recursive $Arguments" `
+            -ForegroundColor Blue
+        git clone --filter=blob:none $URL $PSScriptRoot/../$Path -b $Branch --recursive $Arguments
+    }
+}

libs/SDL3_mixer/external/download.sh

@@ -0,0 +1,23 @@
+#!/bin/sh
+
+set -e
+
+ARGUMENTS="$*"
+
+cd $(dirname "$0")/..
+cat .gitmodules | \
+while true; do
+    read module || break
+    read line; set -- $line
+    path=$3
+    read line; set -- $line
+    url=$3
+    read line; set -- $line
+    branch=$3
+
+    if [ -z "$ARGUMENTS" ]; then
+        ARGUMENTS="--depth 1"
+    fi
+
+    git clone --filter=blob:none $url $path -b $branch --recursive $ARGUMENTS
+done