[PATCH v2] configure: Improve zstd test

[Juan Quintela]

There were one error on the test (missing an s for --exists).
But we really need a recent zstd (1.4.0).
Thanks to Michal Privoznik to provide the right vension.

Signed-off-by: Juan Quintela <address@hidden>
Reported-by: Richard Henderson <address@hidden>
---
 configure | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/configure b/configure
index cbf864bff1..f5454bd603 100755
--- a/configure
+++ b/configure
@@ -2475,7 +2475,8 @@ fi
 # zstd check
 
 if test "$zstd" != "no" ; then
-    if $pkg_config --exist libzstd ; then
+    libzstd_minver="1.4.0"
+    if $pkg_config --atleast-version=$libzstd_minver libzstd ; then
         zstd_cflags="$($pkg_config --cflags libzstd)"
         zstd_libs="$($pkg_config --libs libzstd)"
         LIBS="$zstd_libs $LIBS"
-- 
2.24.1