--- SConstruct.orig	2021-07-07 09:17:06 UTC
+++ SConstruct
@@ -1213,9 +1213,9 @@ 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(list(unknown_vars.keys())))
+#unknown_vars = env_vars.UnknownVariables()
+#if unknown_vars:
+#    env.FatalError("Unknown variables specified: {0}", ", ".join(list(unknown_vars.keys())))
 
 if get_option('install-action') != 'default' and get_option('ninja') != "disabled":
     env.FatalError("Cannot use non-default install actions when generating Ninja.")
@@ -2091,7 +2091,7 @@ 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'],
             )
 
@@ -2106,7 +2106,7 @@ 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"] )
 
@@ -3926,7 +3926,8 @@ def doConfigure(myenv):
     myenv = conf.Finish()
 
     if env['TARGET_ARCH'] == "aarch64":
-        AddToCCFLAGSIfSupported(myenv, "-moutline-atomics")
+        # https://lists.freebsd.org/archives/freebsd-ports/2021-July/000431.html
+        AddToCCFLAGSIfSupported(myenv, "-mno-outline-atomics")
 
     conf = Configure(myenv)
     usdt_enabled = get_option('enable-usdt-probes')