Fix avx512 feature test

The check was broken on non-bash and producing errors like this:

/home/louai/work/qt5/qtbase/configure: 4528: [: Illegal number:

Change-Id: I5e78ad002cd7cfb401f2646510e0923f77c55f98
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/configure b/configure
index 80a335a350..3fbf97143d 100755
--- a/configure
+++ b/configure
@@ -4526,7 +4526,7 @@ if [ "${CFG_AVX512}" = "auto" ]; then
         CFG_AVX512=f
         CFG_AVX512_UPPER=AVX512F
         for feature in er cd pf dq bw vl ifma vbmi; do
-            if [ -n "BASH_VERSION" ] && [ "${BASH_VERSION%%.*}" -gt 3 ]; then
+            if [ -n "$BASH_VERSION" ] && [ "${BASH_VERSION%%.*}" -gt 3 ]; then
                 upper=${feature^^*}
             elif [ -n "$ZSH_VERSION" ]; then
                 upper=${(U)feature}