diff --git a/configure.ac b/configure.ac
index 53a96763e16e89bb744201bb2ffbc56b1123fce3..7bd6a6490b8faa8998c97ab33a7f2a46644d6d8f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -926,12 +926,12 @@ else
     if test `$SWIG -help 2>&1 | $EGREP -c "(-php|-php7) *- Generate"` = 0 ; then
       use_php="No (swig does not support -php or -php7 option)"
     else
-      AC_CHECK_PROGS(PHP,php7.2,php7,php)
-      if test "$PHP" = ""; then
+      AC_CHECK_PROGS(PHP,[php7.2 php7 php], "false")
+      if test "$PHP" = "false"; then
         use_php="No (php not available)"
       else
-        AC_CHECK_PROGS(PHPCONFIG,${PHP}-config,php-config)
-        if test "$PHPCONFIG" = ""; then
+        AC_CHECK_PROGS(PHPCONFIG,[${PHP}-config php-config], "false")
+        if test "$PHPCONFIG" = "false"; then
           use_php="No (php-config not available)"
         else
           PHP_INCLUDES="`$PHPCONFIG --includes`"
@@ -947,7 +947,7 @@ else
           CPPFLAGS=$save_CPPFLAGS
         fi
       fi
-      if test "$PHP" != ""; then
+      if test "$PHP" != "false"; then
 	    use_php="Yes"
         AC_SUBST([PHP_INCLUDES])
         AC_SUBST([PHP_INSTALL_DIR])