diff --git a/Sources/ArgumentParser/Usage/HelpGenerator.swift b/Sources/ArgumentParser/Usage/HelpGenerator.swift
index 39c041c40..eeba86e7e 100644
--- a/Sources/ArgumentParser/Usage/HelpGenerator.swift
+++ b/Sources/ArgumentParser/Usage/HelpGenerator.swift
@@ -325,7 +325,13 @@ func _terminalSize() -> (width: Int, height: Int) {
           height: Int(csbi.srWindow.Bottom - csbi.srWindow.Top) + 1)
 #else
   var w = winsize()
+#if os(OpenBSD)
+  // TIOCGWINSZ is a complex macro, so we need the flattened value.
+  let tiocgwinsz = Int32(0x40087468)
+  let err = ioctl(STDOUT_FILENO, tiocgwinsz, &w)
+#else
   let err = ioctl(STDOUT_FILENO, TIOCGWINSZ, &w)
+#endif
   let width = Int(w.ws_col)
   let height = Int(w.ws_row)
   guard err == 0 else { return (80, 25) }
diff --git a/cmake/modules/SwiftSupport.cmake b/cmake/modules/SwiftSupport.cmake
index b5f2db35d..2b2ac76c6 100644
--- a/cmake/modules/SwiftSupport.cmake
+++ b/cmake/modules/SwiftSupport.cmake
@@ -27,6 +27,8 @@ function(get_swift_host_arch result_var_name)
     set("${result_var_name}" "armv7" PARENT_SCOPE)
   elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "armv7l")
     set("${result_var_name}" "armv7" PARENT_SCOPE)
+  elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "amd64")
+    set("${result_var_name}" "amd64" PARENT_SCOPE)
   elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "AMD64")
     set("${result_var_name}" "x86_64" PARENT_SCOPE)
   elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "IA64")