Import compiler/linker flags from environment

SConstruct

@@ -4,6 +4,20 @@ env = Environment()
 
 if ARGUMENTS.get('debian'):
     env.Append(CPPDEFINES=['__Debian__'])
+flags = ["CPPFLAGS", "CFLAGS", "CXXFLAGS"]
+for flag in flags:
+    try:
+        env[flag] = os.environ[flag]
+        print "Imported \"%s\" from environment with value \"%s\"." % (flag, env[flag])
+    except:
+        print "No \"%s\" in environment found" % flag
+
+# if LDFLAGS exists put them into scons LINKFLAGS
+try:
+    env['LINKFLAGS'] = os.environ['LDFLAGS']
+    print "Imported \"LDFLAGS\" from environment as \"LINKFLAGS\" with value \"%s\"." % env['LINKFLAGS']
+except:
+    print "No \"LDFLAGS\" in environment found."
 
 if os.uname()[0] == 'Linux':
     env.Append(CPPDEFINES=['_HAVE_NCURSES','_HAVE_NCURSES_COLOR'])