diff --git a/config/perl.m4 b/config/perl.m4
index 0b43b04742e..bed2eae57fe 100644
--- a/config/perl.m4
+++ b/config/perl.m4
@@ -13,7 +13,7 @@ if test "$PERL"; then
   pgac_perl_version=`$PERL -v 2>/dev/null | sed -n ['s/This is perl.*v[a-z ]*\([0-9]\.[0-9][0-9.]*\).*$/\1/p']`
   AC_MSG_NOTICE([using perl $pgac_perl_version])
   if echo "$pgac_perl_version" | sed ['s/[.a-z_]/ /g'] | \
-    $AWK '{ if ([$]1 = 5 && [$]2 >= 8) exit 1; else exit 0;}'
+    $AWK '{ if ([$]1 == 5 && [$]2 >= 8) exit 1; else exit 0;}'
   then
     AC_MSG_WARN([
 *** The installed version of Perl, $PERL, is too old to use with PostgreSQL.
diff --git a/config/programs.m4 b/config/programs.m4
index 87f63b6d10c..5fa03c37395 100644
--- a/config/programs.m4
+++ b/config/programs.m4
@@ -77,7 +77,7 @@ else
         echo '%%'  > conftest.l
         if $pgac_candidate -t conftest.l 2>/dev/null | grep FLEX_SCANNER >/dev/null 2>&1; then
           pgac_flex_version=`$pgac_candidate --version 2>/dev/null`
-          if echo "$pgac_flex_version" | sed ['s/[.a-z]/ /g'] | $AWK '{ if ([$]1 = 2 && ([$]2 > 5 || ([$]2 = 5 && [$]3 >= 31))) exit 0; else exit 1;}'
+          if echo "$pgac_flex_version" | sed ['s/[.a-z]/ /g'] | $AWK '{ if ([$]1 == 2 && ([$]2 > 5 || ([$]2 == 5 && [$]3 >= 31))) exit 0; else exit 1;}'
           then
             pgac_cv_path_flex=$pgac_candidate
             break 2
diff --git a/configure b/configure
index e09eb5fb531..ec753182e2b 100755
--- a/configure
+++ b/configure
@@ -7358,7 +7358,7 @@ else
         echo '%%'  > conftest.l
         if $pgac_candidate -t conftest.l 2>/dev/null | grep FLEX_SCANNER >/dev/null 2>&1; then
           pgac_flex_version=`$pgac_candidate --version 2>/dev/null`
-          if echo "$pgac_flex_version" | sed 's/[.a-z]/ /g' | $AWK '{ if ($1 = 2 && ($2 > 5 || ($2 = 5 && $3 >= 31))) exit 0; else exit 1;}'
+          if echo "$pgac_flex_version" | sed 's/[.a-z]/ /g' | $AWK '{ if ($1 == 2 && ($2 > 5 || ($2 == 5 && $3 >= 31))) exit 0; else exit 1;}'
           then
             pgac_cv_path_flex=$pgac_candidate
             break 2
@@ -7456,7 +7456,7 @@ if test "$PERL"; then
   { $as_echo "$as_me:${as_lineno-$LINENO}: using perl $pgac_perl_version" >&5
 $as_echo "$as_me: using perl $pgac_perl_version" >&6;}
   if echo "$pgac_perl_version" | sed 's/[.a-z_]/ /g' | \
-    $AWK '{ if ($1 = 5 && $2 >= 8) exit 1; else exit 0;}'
+    $AWK '{ if ($1 == 5 && $2 >= 8) exit 1; else exit 0;}'
   then
     { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING:
 *** The installed version of Perl, $PERL, is too old to use with PostgreSQL.