configure.ac: Disable metalink support if an incompatible SSL/TLS specified

tool_metalink only supports cryptography from OpenSSL, GnuTLS, NSS,
The Win32 Crypto library and Apple's Common Crypto library.

If an TLS backend such as mbedTLS or WolfSSL is specified then the
following error is given during compilation along, with a load of
unresolved extern errors:

Can't compile METALINK support without a crypto library.

Reviewed-by: Daniel Stenberg
Closes #5006

diff --git a/configure.ac b/configure.ac
index bde7d88538d7fa8c70648f0554faca800c530645..6feab9284d1ea4c5252806057ea0d042e3545cea 100755 (executable)
--- a/configure.ac
+++ b/configure.ac
@@ -2770,6 +2770,12 @@ if test X"$OPT_LIBMETALINK" != Xno; then
       AC_MSG_NOTICE([libmetalink library defective or too old])
       want_metalink="no"
     ])
+    if test "x$OPENSSL_ENABLED" != "x1" -a "x$USE_WINDOWS_SSPI" != "x1" \
+        -a "x$GNUTLS_ENABLED" != "x1" -a "x$MBEDTLS_ENABLED" != "x1" \
+        -a "x$NSS_ENABLED" != "x1" -a "x$SECURETRANSPORT_ENABLED" != "x1"; then
+      AC_MSG_WARN([metalink support requires a compatible SSL/TLS backend])
+      want_metalink="no"
+    fi
     CPPFLAGS="$clean_CPPFLAGS"
     LDFLAGS="$clean_LDFLAGS"
     LIBS="$clean_LIBS"