diff --git a/SCons/Config/gnu b/SCons/Config/gnu
index e3d1e1cd..98b043b4 100644
--- a/SCons/Config/gnu
+++ b/SCons/Config/gnu
@@ -102,10 +102,11 @@ makensis_env = tdefenv.Clone()
 makensis_env.Append(CPPPATH = ['#$BUILD_CONFIG'])
 
 if not defenv['DEBUG']:
-	makensis_env.Append(CCFLAGS = ['-O2'])                  # optimize
+	makensis_env.Append(CCFLAGS = ['-O2'])                # optimize
 makensis_env.Append(CFLAGS = ['-Wall'])                   # all warnings
 makensis_env.Append(CXXFLAGS = ['-Wno-non-virtual-dtor']) # ignore virtual dtor warnings
 makensis_env.Append(CXXFLAGS = ['-Wall'])                 # all warnings
+makensis_env['STDCALL'] = ''                              # avoid warnings
 
 conf = FlagsConfigure(makensis_env)
 conf.CheckLinkFlag('$MAP_FLAG')                   # generate map file