Build with assertions on in release build

SConstruct

@@ -52,10 +52,11 @@ AddOption('--coverage',
             help='Build with coverage (gcov) support'
 )
 
-AddOption('--with-assertions',
+AddOption('--without-assertions',
             dest='assertions',
-            action='store_true',
+            action='store_false',
-            help='Build with assertions enabled (Default for a debug build)'
+            default=True,
+            help='Build without assertions enabled'
 )
 
 AddOption('--stack-protection',
@@ -110,11 +111,6 @@ if GetOption('force32bit'):
 
 if build_type == 'release':
     env.Append(CFLAGS = ['-O2'])
-
-    if not assertions:
-        #this will turn off assert()
-        env.Append(CPPDEFINES = ['NDEBUG'])
-
 elif build_type == 'debug':
     lib_suffix = 'D'
     env.Append(CPPDEFINES = ['DEBUG'])
@@ -122,6 +118,9 @@ elif build_type == 'debug':
 if stack_protection:
     env.Append(CFLAGS = ['-fstack-protector', '--param=ssp-buffer-size=4'])
     env.Append(CPPDEFINES = ['_FORTIFY_SOURCE=2'])
+if not assertions:
+    #this will turn off assert()
+    env.Append(CPPDEFINES = ['NDEBUG'])
 
 if GetOption('coverage'):
     env.Append(CFLAGS = ['--coverage'])
@@ -131,6 +130,7 @@ if GetOption('coverage'):
 subst_info = dict(('@' + key + '@', version_info[key]) for key in version_info)
 subst_info['@prefix@'] = prefix
 subst_info['@build_type@'] = build_type
+
 if assertions:
     subst_info['@build_type@'] += '_A'
 if stack_protection: