configure: if asked to use TLS, fail if no TLS lib was detected

Previously the configure script would just warn about this fact and
continue with TLS disabled build which is not always helpful. TLS should
be explicitly disabled if that is what the user wants.

Closes #9367

diff --git a/configure.ac b/configure.ac
index 7d5750c9228b70f16a29eca965f73de6f81926b8..30c881f3fc809655ea42b2a45d5887547e508328 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -218,6 +218,8 @@ AS_HELP_STRING([--without-ssl], [build without any TLS library]),[
   OPT_OPENSSL=$withval
   if test X"$withval" != Xno; then
     TLSCHOICE="${TLSCHOICE:+$TLSCHOICE, }OpenSSL"
+  else
+    SSL_DISABLED="D"
   fi
 ])
 
@@ -1955,11 +1957,11 @@ if test "x$curl_cv_native_windows" = "xyes" &&
   LIBS="-lbcrypt $LIBS"
 fi
 
-case "x$OPENSSL_ENABLED$GNUTLS_ENABLED$NSS_ENABLED$MBEDTLS_ENABLED$WOLFSSL_ENABLED$SCHANNEL_ENABLED$SECURETRANSPORT_ENABLED$BEARSSL_ENABLED$RUSTLS_ENABLED"
+case "x$OPENSSL_ENABLED$GNUTLS_ENABLED$NSS_ENABLED$MBEDTLS_ENABLED$WOLFSSL_ENABLED$SCHANNEL_ENABLED$SECURETRANSPORT_ENABLED$BEARSSL_ENABLED$RUSTLS_ENABLED$SSL_DISABLED"
 in
 x)
-  AC_MSG_WARN([SSL disabled, you will not be able to use HTTPS, FTPS, NTLM and more.])
-  AC_MSG_WARN([Use --with-openssl, --with-gnutls, --with-wolfssl, --with-mbedtls, --with-nss, --with-schannel, --with-secure-transport, --with-amissl, --with-bearssl or --with-rustls to address this.])
+  AC_MSG_ERROR([TLS not detected, you will not be able to use HTTPS, FTPS, NTLM and more.
+Use --with-openssl, --with-gnutls, --with-wolfssl, --with-mbedtls, --with-nss, --with-schannel, --with-secure-transport, --with-amissl, --with-bearssl or --with-rustls to address this.])
   ;;
 x1)
   # one SSL backend is enabled
@@ -1967,6 +1969,9 @@ x1)
   SSL_ENABLED="1"
   AC_MSG_NOTICE([built with one SSL backend])
   ;;
+xD)
+  # explicitly built without TLS
+  ;;
 *)
   # more than one SSL backend is enabled
   AC_SUBST(SSL_ENABLED)