feature: add buildmode=wasi-legacy to support existing base of users who expected the

older behavior for wasi modules to not return an exit code as if they were reactors.

See #4726 for some details on what this is intended to address.

Signed-off-by: deadprogram <ron@hybridgroup.com>

compileopts/options.go

@@ -8,7 +8,7 @@ import (
 )
 
 var (
-	validBuildModeOptions     = []string{"default", "c-shared"}
+	validBuildModeOptions     = []string{"default", "c-shared", "wasi-legacy"}
 	validGCOptions            = []string{"none", "leaking", "conservative", "custom", "precise"}
 	validSchedulerOptions     = []string{"none", "tasks", "asyncify"}
 	validSerialOptions        = []string{"none", "uart", "usb", "rtt"}