Trac #33390: singular spkg-configure.m4: Better test for help

As reported in https://groups.google.com/g/sage-
release/c/vxYHQA6LUGw/m/_LO2GLLlAAAJ, the current test is not suitable
on some systems.

URL: https://trac.sagemath.org/33390
Reported by: mkoeppe
Ticket author(s): Steven Trogdon
Reviewer(s): Matthias Koeppe

build/pkgs/singular/spkg-configure.m4

@@ -6,7 +6,7 @@ SAGE_SPKG_CONFIGURE([singular], [
       dnl Use pkg-config to ensure that Singular is new enough.
       PKG_CHECK_MODULES([SINGULAR], [Singular >= 4.2.1], [
        AC_MSG_CHECKING([that Singular's help is working])
-       AS_IF([test x`echo "help;" | Singular 2>&1 | grep "error\ occurred"` = x], [
+       AS_IF([test x`echo -e "system(\"--browser\", \"builtin\"); \n help;" | Singular 2>&1 | grep "error\ occurred"` = x], [
         AC_MSG_RESULT(yes)
         dnl We have Singular. Now determine the shared library path on
         dnl platforms on which sage.libs.singular needs to reload the library with RTLD_GLOBAL.