diff --git a/waf-tools/flags.py b/waf-tools/flags.py
new file mode 100644
index 0000000..416b772
--- /dev/null
+++ b/waf-tools/flags.py
@@ -0,0 +1,39 @@
+#! /usr/bin/env python
+# encoding: utf-8
+
+from waflib import Configure
+
+@Configure.conf
+def add_supported_cflags(self, cflags):
+    """
+    Check which cflags are supported by compiler and add them to env.CFLAGS variable
+    """
+    self.start_msg('Checking allowed flags for c compiler')
+
+    supportedFlags = []
+    for flag in cflags:
+        if self.check_cc (cflags=[flag], mandatory=False):
+            supportedFlags += [flag]
+
+    self.end_msg (' '.join (supportedFlags))
+    self.env.CFLAGS += supportedFlags
+
+def configure(conf):
+    conf.load ('gnu_dirs')
+    
+    if conf.options.debug:
+        conf.define ('_DEBUG', 1)
+        conf.add_supported_cflags (cflags = ['-O0',
+                                             '-Wall',
+                                             '-Wno-unused-variable',
+                                             '-g3',
+                                             '-Wno-unused-private-field', # only clang supports
+                                             '-fcolor-diagnostics',       # only clang supports
+                                             '-Qunused-arguments'         # only clang supports
+                                             ])
+    else:
+        conf.add_supported_cflags (cflags = ['-O3', '-g'])
+
+def options(opt):
+    opt.load ('gnu_dirs')
+    opt.add_option('--debug',action='store_true',default=False,dest='debug',help='''debugging mode''')