Fix ARM64 host detection: force win-x64 Firebird on ARM64 Windows

On windows-11-arm building for x64 (emulation), Architecture is 'x64'
so FirebirdRid was empty. PSFirebird auto-detected win-arm64 which has
no usable Firebird binaries. Detect ARM64 host and explicitly request
win-x64 Firebird.

Author: fdcastel

firebird-odbc-driver.build.ps1

@@ -51,6 +51,13 @@ $FirebirdRid = switch ($Architecture) {
 	default { '' }
 }
 
+# On ARM64 Windows hosts building for x64 (emulation), explicitly request
+# win-x64 Firebird since PSFirebird would otherwise auto-detect win-arm64.
+if (-not $FirebirdRid -and $IsWindowsOS -and
+	[System.Runtime.InteropServices.RuntimeInformation]::OSArchitecture -eq 'Arm64') {
+	$FirebirdRid = 'win-x64'
+}
+
 # Synopsis: Remove the build directory.
 task clean {
 	remove $BuildDir