@@ -113,10 +113,22 @@
 dnl Find "xxd" so we can build the tls.tcl.h file
 AC_CHECK_PROG([XXD], [xxd], [xxd], [__xxd__not__found])
 
 dnl Find "pkg-config" since we need to use it
 AC_CHECK_TOOL([PKGCONFIG], [pkg-config], [false])
+
+dnl Determine if we have been asked to use a fast path if possible
+tcltls_ssl_fastpath='yes'
+AC_ARG_ENABLE([ssl-fastpath], AS_HELP_STRING([--disable-ssl-fast-path], [disable using the underlying file descriptor for talking directly to the SSL library]), [
+	if test "$enableval" = 'no'; then
+		tcltls_ssl_fastpath='no'
+	fi
+])
+
+if test "$tcltls_ssl_fastpath" = 'yes'; then
+	AC_DEFINE(TCLTLS_SSL_USE_FASTPATH, [1], [Define this to enable using the underlying file descriptor for talking directly to the SSL library])
+fi
 
 dnl Determine if we have been asked to statically link to the SSL library
 TCLEXT_TLS_STATIC_SSL='no'
 AC_ARG_ENABLE([static-ssl], AS_HELP_STRING([--enable-static-ssl], [enable statically linking to the specified SSL library]), [
 	if test "$enableval" = 'yes'; then