--- SConstruct.orig	2018-01-04 23:28:55 UTC
+++ SConstruct
@@ -922,9 +922,9 @@ if has_option('variables-help'):
     print(env_vars.GenerateHelpText(env))
     Exit(0)
 
-unknown_vars = env_vars.UnknownVariables()
-if unknown_vars:
-    env.FatalError("Unknown variables specified: {0}", ", ".join(unknown_vars.keys()))
+#unknown_vars = env_vars.UnknownVariables()
+#if unknown_vars:
+#    env.FatalError("Unknown variables specified: {0}", ", ".join(unknown_vars.keys()))
 
 def set_config_header_define(env, varname, varval = 1):
     env['CONFIG_HEADER_DEFINES'][varname] = varval
@@ -1612,7 +1612,7 @@ if env.TargetOSIs('posix'):
             # If runtime hardening is requested, then build anything
             # destined for an executable with the necessary flags for PIE.
             env.AppendUnique(
-                PROGCCFLAGS=['-fPIE'],
+                PROGCCFLAGS=['-fpic'],
                 PROGLINKFLAGS=['-pie'],
             )
 
@@ -1626,7 +1626,7 @@ if env.TargetOSIs('posix'):
                          "-Wno-unknown-pragmas",
                          "-Winvalid-pch"] )
     # env.Append( " -Wconversion" ) TODO: this doesn't really work yet
-    if env.TargetOSIs('linux', 'darwin', 'solaris'):
+    if env.TargetOSIs('linux', 'darwin', 'solaris', 'freebsd'):
         if not has_option("disable-warnings-as-errors"):
             env.Append( CCFLAGS=["-Werror"] )