diff --git a/buildtools/wafsamba/samba_autoconf.py b/buildtools/wafsamba/samba_autoconf.py
index 8b499825230..78927d85193 100644
--- a/buildtools/wafsamba/samba_autoconf.py
+++ b/buildtools/wafsamba/samba_autoconf.py
@@ -343,6 +343,23 @@ def CHECK_SIZEOF(conf, vars, headers=None, define=None, critical=True):
             sys.exit(1)
     return ret
 
+@conf
+def CHECK_SIGN(conf, v, headers=None):
+    '''check the sign of a type'''
+    define_name = v.upper().replace(' ', '_')
+    for op, signed in [('<', 'signed'),
+                       ('>', 'unsigned')]:
+        if CHECK_CODE(conf,
+                      f'static int test_array[1 - 2 * !((({v})-1) {op} 0)];',
+                      define=f'{define_name}_{signed.upper()}',
+                      quote=False,
+                      headers=headers,
+                      local_include=False,
+                      msg=f"Checking if '{v}' is {signed}"):
+            return True
+
+    return False
+
 @conf
 def CHECK_VALUEOF(conf, v, headers=None, define=None):
     '''check the value of a variable/define'''
diff --git a/third_party/heimdal_build/wscript_configure b/third_party/heimdal_build/wscript_configure
index 023935d98c0..0021cd328ec 100644
--- a/third_party/heimdal_build/wscript_configure
+++ b/third_party/heimdal_build/wscript_configure
@@ -206,3 +206,5 @@ if conf.CONFIG_SET('USING_EMBEDDED_HEIMDAL'):
     conf.define('HAVE_KRB5_ADDLOG_FUNC_NEED_CONTEXT', 1)
 else:
     pass # TODO
+
+conf.CHECK_SIGN('time_t')