* tests/priority_queue_unit_test.cc: New test.

configure.ac

@@ -320,12 +320,15 @@ AC_PATH_PROGS(MAKEINFO, makeinfo true)
 
 AC_PROG_CC
 gl_EARLY
+AC_PROG_CXX
 AM_PROG_CC_C_O
 AM_PROG_AS
 
 # Must be GCC.
 test "x$GCC" = xyes || AC_MSG_ERROR([GCC is required])
 
+AC_CHECK_PROG(HAVE_CXX, $CXX, yes, no)
+
 AC_GNU_SOURCE
 AM_GNU_GETTEXT([external])
 AC_SYS_LARGEFILE
@@ -1178,6 +1181,8 @@ AM_CONDITIONAL([COND_ENABLE_EFIEMU], [test x$enable_efiemu = xyes])
 AM_CONDITIONAL([COND_ENABLE_CACHE_STATS], [test x$DISK_CACHE_STATS = x1])
 AM_CONDITIONAL([COND_ENABLE_BOOT_TIME_STATS], [test x$BOOT_TIME_STATS = x1])
 
+AM_CONDITIONAL([COND_HAVE_CXX], [test x$HAVE_CXX = xyes])
+
 AM_CONDITIONAL([COND_HAVE_ASM_USCORE], [test x$HAVE_ASM_USCORE = x1])
 AM_CONDITIONAL([COND_CYGWIN], [test x$host_os = xcygwin])
 AM_CONDITIONAL([COND_STARFIELD], [test "x$starfield_excuse" = x])