configure.ac: add a MesaLink vtls backend

configure.ac

@@ -158,7 +158,7 @@ AC_SUBST(PKGADD_VENDOR)
 
 dnl
 dnl initialize all the info variables
-    curl_ssl_msg="no      (--with-{ssl,gnutls,nss,polarssl,mbedtls,cyassl,axtls,winssl,darwinssl} )"
+    curl_ssl_msg="no      (--with-{ssl,gnutls,nss,polarssl,mbedtls,cyassl,axtls,winssl,darwinssl,mesalink} )"
     curl_ssh_msg="no      (--with-libssh2)"
    curl_zlib_msg="no      (--with-zlib)"
  curl_brotli_msg="no      (--with-brotli)"
@@ -2409,6 +2409,98 @@ if test -z "$ssl_backends" -o "x$OPT_CYASSL" != xno; then
   test -z "$ssl_msg" || ssl_backends="${ssl_backends:+$ssl_backends, }$ssl_msg"
 fi
 
+dnl ----------------------------------------------------
+dnl check for MesaLink
+dnl ----------------------------------------------------
+
+dnl Default to compiler & linker defaults for MesaLink files & libraries.
+OPT_MESALINK=no
+
+_cppflags=$CPPFLAGS
+_ldflags=$LDFLAGS
+AC_ARG_WITH(mesalink,dnl
+AC_HELP_STRING([--with-mesalink=PATH],[where to look for MesaLink, PATH points to the installation root])
+AC_HELP_STRING([--without-mesalink], [disable MesaLink detection]),
+  OPT_MESALINK=$withval)
+
+if test -z "$ssl_backends" -o "x$OPT_MESALINK" != xno; then
+  ssl_msg=
+
+  if test X"$OPT_MESALINK" != Xno; then
+
+    if test "$OPT_MESALINK" = "yes"; then
+      OPT_MESALINK=""
+    fi
+
+    if test -z "$OPT_MESALINK" ; then
+      dnl check for lib first without setting any new path
+
+      AC_CHECK_LIB(mesalink, mesalink_library_init,
+      dnl libmesalink found, set the variable
+       [
+         AC_DEFINE(USE_MESALINK, 1, [if MesaLink is enabled])
+         AC_SUBST(USE_MESALINK, [1])
+         MESALINK_ENABLED=1
+         USE_MESALINK="yes"
+         ssl_msg="MesaLink"
+	 test mesalink != "$DEFAULT_SSL_BACKEND" || VALID_DEFAULT_SSL_BACKEND=yes
+        ])
+    fi
+
+    addld=""
+    addlib=""
+    addcflags=""
+    mesalinklib=""
+
+    if test "x$USE_MESALINK" != "xyes"; then
+      dnl add the path and test again
+      addld=-L$OPT_MESALINK/lib$libsuff
+      addcflags=-I$OPT_MESALINK/include
+      mesalinklib=$OPT_MESALINK/lib$libsuff
+
+      LDFLAGS="$LDFLAGS $addld"
+      if test "$addcflags" != "-I/usr/include"; then
+         CPPFLAGS="$CPPFLAGS $addcflags"
+      fi
+
+      AC_CHECK_LIB(mesalink, mesalink_library_init,
+       [
+       AC_DEFINE(USE_MESALINK, 1, [if MesaLink is enabled])
+       AC_SUBST(USE_MESALINK, [1])
+       MESALINK_ENABLED=1
+       USE_MESALINK="yes"
+       ssl_msg="MesaLink"
+       test mesalink != "$DEFAULT_SSL_BACKEND" || VALID_DEFAULT_SSL_BACKEND=yes
+       ],
+       [
+         CPPFLAGS=$_cppflags
+         LDFLAGS=$_ldflags
+       ])
+    fi
+
+    if test "x$USE_MESALINK" = "xyes"; then
+      AC_MSG_NOTICE([detected MesaLink])
+
+      LIBS="-lmesalink $LIBS"
+
+      if test -n "$mesalinklib"; then
+        dnl when shared libs were found in a path that the run-time
+        dnl linker doesn't search through, we need to add it to
+        dnl LD_LIBRARY_PATH to prevent further configure tests to fail
+        dnl due to this
+        if test "x$cross_compiling" != "xyes"; then
+          LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$mesalinklib"
+          export LD_LIBRARY_PATH
+          AC_MSG_NOTICE([Added $mesalinklib to LD_LIBRARY_PATH])
+        fi
+      fi
+    fi
+
+  fi dnl MesaLink not disabled
+
+  test -z "$ssl_msg" || ssl_backends="${ssl_backends:+$ssl_backends, }$ssl_msg"
+fi
+
 dnl ----------------------------------------------------
 dnl NSS. Only check if GnuTLS and OpenSSL are not enabled
 dnl ----------------------------------------------------
@@ -2599,10 +2691,10 @@ if test -z "$ssl_backends" -o "x$OPT_AXTLS" != xno; then
   test -z "$ssl_msg" || ssl_backends="${ssl_backends:+$ssl_backends, }$ssl_msg"
 fi
 
-case "x$OPENSSL_ENABLED$GNUTLS_ENABLED$NSS_ENABLED$POLARSSL_ENABLED$MBEDTLS_ENABLED$AXTLS_ENABLED$CYASSL_ENABLED$WINSSL_ENABLED$DARWINSSL_ENABLED" in
+case "x$OPENSSL_ENABLED$GNUTLS_ENABLED$NSS_ENABLED$POLARSSL_ENABLED$MBEDTLS_ENABLED$AXTLS_ENABLED$CYASSL_ENABLED$WINSSL_ENABLED$DARWINSSL_ENABLED$MESALINK_ENABLED" in
 x)
   AC_MSG_WARN([SSL disabled, you will not be able to use HTTPS, FTPS, NTLM and more.])
-  AC_MSG_WARN([Use --with-ssl, --with-gnutls, --with-polarssl, --with-cyassl, --with-nss, --with-axtls, --with-winssl, or --with-darwinssl to address this.])
+  AC_MSG_WARN([Use --with-ssl, --with-gnutls, --with-polarssl, --with-cyassl, --with-nss, --with-axtls, --with-winssl, --with-darwinssl, or --with-mesalink to address this.])
   ;;
 x1)
   # one SSL backend is enabled

lib/Makefile.inc

@@ -30,12 +30,12 @@ LIB_VAUTH_HFILES = vauth/vauth.h vauth/digest.h vauth/ntlm.h
 LIB_VTLS_CFILES = vtls/openssl.c vtls/gtls.c vtls/vtls.c vtls/nss.c     \
   vtls/polarssl.c vtls/polarssl_threadlock.c vtls/axtls.c               \
   vtls/cyassl.c vtls/schannel.c vtls/schannel_verify.c                  \
-  vtls/darwinssl.c vtls/gskit.c vtls/mbedtls.c
+  vtls/darwinssl.c vtls/gskit.c vtls/mbedtls.c vtls/mesalink.c
 
 LIB_VTLS_HFILES = vtls/openssl.h vtls/vtls.h vtls/gtls.h                \
   vtls/nssg.h vtls/polarssl.h vtls/polarssl_threadlock.h vtls/axtls.h   \
   vtls/cyassl.h vtls/schannel.h vtls/darwinssl.h vtls/gskit.h           \
-  vtls/mbedtls.h
+  vtls/mbedtls.h vtls/mesalink.h
 
 LIB_CFILES = file.c timeval.c base64.c hostip.c progress.c formdata.c   \
   cookie.c http.c sendf.c ftp.c url.c dict.c if2ip.c speedcheck.c       \