+dnl Check to find the OpenSSL headers/libraries
+
+
+AC_DEFUN(tinc_OPENSSL,
+[
+
+ AC_CACHE_CHECK([for openssl], tinc_cv_openssl_include,
+ [
+ AC_ARG_WITH(openssl,
+ [ --with-openssl=DIR OpenSSL library and headers prefix],
+ [echo -ne 'prefix...'
+ openssl_lib="$withval/lib"
+ openssl_include="$withval/include"]
+ )
+ AC_ARG_WITH(openssl-include,
+ [ --with-openssl-include=DIR OpenSSL headers directory],
+ [echo -ne 'includes...'
+ openssl_include="$withvall"]
+ )
+ AC_ARG_WITH(openssl-lib,
+ [ --with-openssl-lib=DIR OpenSSL library directory],
+ [echo -ne 'libraries...'
+ openssl_lib="$withval"]
+ )
+
+if test "x$openssl_lib" != "x" ; then
+ LIBS="$LIBS -L$openssl_lib"
+fi
+if test "x$openssl_include" != "x" ; then
+ INCLUDES="$INCLUDES -I$openssl_include"
+fi
+
+AC_MSG_RESULT([done.])
+ ])
+
+libcrypto=none
+AC_CHECK_LIB(crypto, SHA1_version, [
+ libcrypto=yes
+])
+
+if test $libcrypto = none; then
+ AC_MSG_ERROR(
+[It seems like OpenSSL is not installed on this system. But perhaps
+you need to supply the exact location of the headers and libraries.
+You can try running configure with the --with-openssl=/DIRECTORY
+parameter. If you installed the headers and libraries in a different
+location you can use --with-openssl-include=/DIR and
+--with-openssl-lib=/DIR.])
+
+else
+ LIBS="$LIBS -lcrypto"
+fi
+
+])