configure: avoid unportable `==' test(1) operator

Closes https://github.com/curl/curl/pull/4567

diff --git a/configure.ac b/configure.ac
index cb8f4943e5a79912aebf2efe17897a1a0298e124..2139f55a8420c52bbc7706f84c9669717c35b6f2 100755 (executable)
--- a/configure.ac
+++ b/configure.ac
@@ -4449,7 +4449,7 @@ if test "x$want_esni" != "xno"; then
 
   dnl OpenSSL with a chosen ESNI function should be enough
   dnl so more exhaustive checking seems unnecessary for now
-  if test "x$OPENSSL_ENABLED" == "x1"; then
+  if test "x$OPENSSL_ENABLED" = "x1"; then
     AC_CHECK_FUNCS(SSL_get_esni_status,
       ESNI_SUPPORT="ESNI support available (OpenSSL with SSL_get_esni_status)"
       ESNI_ENABLED=1)
@@ -4458,7 +4458,7 @@ if test "x$want_esni" != "xno"; then
   fi
 
   dnl now deal with whatever we found
-  if test "x$ESNI_ENABLED" == "x1"; then
+  if test "x$ESNI_ENABLED" = "x1"; then
     AC_DEFINE(USE_ESNI, 1, [if ESNI support is available])
     AC_MSG_RESULT($ESNI_SUPPORT)
     experimental="$experimental ESNI"