Provisioning: Install i686 mingw on Windows 10 X64

Required to compile 32-bit binaries.

Fixes: QTQAINFRA-2896
Change-Id: I91a43ecf6e2c97886429c34c79591999b908879f
Reviewed-by: Heikki Halmet <heikki.halmet@qt.io>

coin/provisioning/common/windows/install-mingw.ps1

@@ -37,7 +37,8 @@ function InstallMinGW
 {
     Param (
         [string] $release = $(BadParam("release file name")),
-        [string] $sha1    = $(BadParam("SHA1 checksum of the file"))
+        [string] $sha1    = $(BadParam("SHA1 checksum of the file")),
+        [string] $suffix  = ""
     )
 
     $arch, $version, $null, $threading, $ex_handling, $build_ver, $revision = $release.split('-')
@@ -45,7 +46,7 @@ function InstallMinGW
     if ($arch -eq "i686") { $win_arch = "Win32" }
     elseif ($arch -eq "x86_64") { $win_arch = "Win64" }
 
-    $envvar = "MINGW$version"
+    $envvar = "MINGW$version$suffix"
     $envvar = $envvar -replace '["."]'
     $targetdir = "C:\$envvar"
     $url_cache = "\\ci-files01-hki.intra.qt.io\provisioning\windows\" + $release + ".7z"

coin/provisioning/qtci-windows-10-x86_64/09-install-mingw730.ps1

@@ -0,0 +1,11 @@
+. "$PSScriptRoot\..\common\windows\install-mingw.ps1"
+
+# This script will install MinGW 7.3.0
+
+$release = "i686-7.3.0-release-posix-dwarf-rt_v5-rev0"
+$sha1 = "96e11c754b379c093e1cb3133f71db5b9f3e0532"
+$suffix = "_i686"
+
+InstallMinGW $release $sha1 $suffix
+
+