Index: Makefile.in
==================================================================
--- Makefile.in
+++ Makefile.in
@@ -12,16 +12,16 @@
 VPATH = @srcdir@
 
 all: @EXTENSION_TARGET@
 
 # The shared object target
-tcltls.@SHOBJEXT@: tls.o tls_openssl_bio.o tlsIO.o tlsX509.o Makefile
-	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -o tcltls.@SHOBJEXT@ tls.o tls_openssl_bio.o tlsIO.o tlsX509.o $(LIBS)
+tcltls.@SHOBJEXT@: tls.o tls_@TCLTLS_SSL_LIB@_bio.o tlsIO.o tlsX509.o Makefile
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(LDFLAGS) -o tcltls.@SHOBJEXT@ tls.o tls_@TCLTLS_SSL_LIB@_bio.o tlsIO.o tlsX509.o $(LIBS)
 
 # The static target
-tcltls.@AREXT@: tls.o tls_openssl_bio.o tlsIO.o tlsX509.o Makefile
-	$(AR) rcu tcltls.a.new tls.o tls_openssl_bio.o tlsIO.o tlsX509.o
+tcltls.@AREXT@: tls.o tls_@TCLTLS_SSL_LIB@_bio.o tlsIO.o tlsX509.o Makefile
+	$(AR) rcu tcltls.a.new tls.o tls_@TCLTLS_SSL_LIB@_bio.o tlsIO.o tlsX509.o
 	$(RANLIB) tcltls.a.new
 	mv tcltls.a.new tcltls.a
 
 # Dependencies for all our targets
 tls.o: @srcdir@/tls.c @srcdir@/tlsInt.h @srcdir@/tclOpts.h @srcdir@/tls.tcl.h dh_params.h Makefile

Index: configure.in
==================================================================
--- configure.in
+++ configure.in
@@ -129,10 +129,12 @@
 if test "$tcltls_ssl_lib" = 'auto'; then
 	tcltls_ssl_lib='openssl'
 fi
 
 AC_MSG_CHECKING([which TLS library to use])
+TCLTLS_SSL_LIB="${tcltls_ssl_lib}"
+AC_SUBST(TCLTLS_SSL_LIB)
 AC_MSG_RESULT([$tcltls_ssl_lib])
 
 dnl Manually rewrite libressl to OpenSSL since we use the
 dnl compatibility interface
 if test "$tcltls_ssl_lib" = "libressl"; then
@@ -140,10 +142,11 @@
 fi
 
 AS_CASE([$tcltls_ssl_lib],
 	[openssl], [
 		TCLTLS_SSL_OPENSSL
+		AC_DEFINE([TCLTLS_SSL_OPENSSL], [1], [Define if the backend being used is OpenSSL (or the LibreSSL OpenSSL compatibility interface)])
 	],
 	[nss], [
 	 	TCLTLS_SSL_LIBS=""
 		TCLTLS_SSL_CFLAGS=""
 		TCLTLS_SSL_CPPFLAGS=""