@@ -13,14 +13,19 @@
 			])
 		], [
 			AC_LANG_PUSH(C)
 			AC_MSG_CHECKING([for $3 protocol support])
 			AC_COMPILE_IFELSE([AC_LANG_PROGRAM([
-#include <openssl/ssl.h>
-#include <openssl/opensslv.h>
+#ifdef OPENSSL_HEADER_PREFIX
+#  define OPENSSL_HEADER(header) <OPENSSL_HEADER_PREFIX/header>
+#else
+#  define OPENSSL_HEADER(header) <header>
+#endif
+#include OPENSSL_HEADER(openssl/ssl.h)
+#include OPENSSL_HEADER(openssl/opensslv.h)
 #if (SSLEAY_VERSION_NUMBER >= 0x0907000L)
-# include <openssl/conf.h>
+# include OPENSSL_HEADER(openssl/conf.h)
 #endif
 			], [
 int x = $5;
 			])], [
 				AC_MSG_RESULT([yes])
@@ -81,10 +86,13 @@
 			openssldir="`AS_DIRNAME(["$openssldir"])`"
 		else
 			TCLTLS_SSL_LIBS="-L$openssldir/lib -lssl -lcrypto"
 		fi
 		TCLTLS_SSL_CFLAGS="-I$openssldir/include"
+		if test -n "$openssldir"; then
+			AC_DEFINE_UNQUOTED(OPENSSL_HEADER_PREFIX, [$openssldir/include], [Path to OpenSSL headers])
+		fi
 		TCLTLS_SSL_CPPFLAGS="-I$openssldir/include"
 	fi
 
 	pkgConfigExtraArgs=''
 	if test "$TCLEXT_BUILD" = "static" -o "$TCLEXT_TLS_STATIC_SSL" = 'yes'; then
@@ -112,10 +120,14 @@
 	if test -z "$TCLTLS_SSL_CFLAGS"; then
 		TCLTLS_SSL_CFLAGS="`"${PKGCONFIG}" openssl --cflags-only-other $pkgConfigExtraArgs`" || AC_MSG_ERROR([Unable to get OpenSSL Configuration])
 	fi
 	if test -z "$TCLTLS_SSL_CPPFLAGS"; then
 		TCLTLS_SSL_CPPFLAGS="`"${PKGCONFIG}" openssl --cflags-only-I $pkgConfigExtraArgs`" || AC_MSG_ERROR([Unable to get OpenSSL Configuration])
+		opensslincdir="$(echo "${TCLTLS_SSL_CPPFLAGS}" | sed 's@^.*-I@@')"
+		if test -n "$opensslincdir"; then
+			AC_DEFINE_UNQUOTED(OPENSSL_HEADER_PREFIX, [$opensslincdir], [Path to OpenSSL headers])
+		fi
 	fi
 	PKG_CONFIG_PATH="${PKG_CONFIG_PATH_SAVE}"
 
 	if test "$TCLEXT_BUILD" = "static"; then
 		dnl If we are doing a static build, save the linker flags for other programs to consume
@@ -164,14 +176,19 @@
 
 	dnl Verify that basic functionality is there
 	AC_LANG_PUSH(C)
 	AC_MSG_CHECKING([if a basic OpenSSL program works])
 	AC_LINK_IFELSE([AC_LANG_PROGRAM([
-#include <openssl/ssl.h>
-#include <openssl/opensslv.h>
+#ifdef OPENSSL_HEADER_PREFIX
+#  define OPENSSL_HEADER(header) <OPENSSL_HEADER_PREFIX/header>
+#else
+#  define OPENSSL_HEADER(header) <header>
+#endif
+#include OPENSSL_HEADER(openssl/ssl.h)
+#include OPENSSL_HEADER(openssl/opensslv.h)
 #if (SSLEAY_VERSION_NUMBER >= 0x0907000L)
-# include <openssl/conf.h>
+# include OPENSSL_HEADER(openssl/conf.h)
 #endif
 		], [
   SSL_library_init();
   SSL_load_error_strings();
 		])], [
@@ -192,13 +209,18 @@
 
 	AC_CACHE_VAL([tcltls_cv_func_tlsext_hostname], [
 		AC_LANG_PUSH(C)
 		AC_MSG_CHECKING([for SSL_set_tlsext_host_name])
 		AC_LINK_IFELSE([AC_LANG_PROGRAM([
-#include <openssl/ssl.h>
+#ifdef OPENSSL_HEADER_PREFIX
+#  define OPENSSL_HEADER(header) <OPENSSL_HEADER_PREFIX/header>
+#else
+#  define OPENSSL_HEADER(header) <header>
+#endif
+#include OPENSSL_HEADER(openssl/ssl.h)
 #if (SSLEAY_VERSION_NUMBER >= 0x0907000L)
-# include <openssl/conf.h>
+# include OPENSSL_HEADER(openssl/conf.h)
 #endif
 			], [
   (void)SSL_set_tlsext_host_name((void *) 0, (void *) 0);
 			])], [
 			AC_MSG_RESULT([yes])