add BeforeExec and AfterExec symbols to stubbed function

Signed-off-by: leongross <[email protected]>

Author: leongross

src/runtime/proc.go

@@ -0,0 +1,11 @@
+package runtime
+
+// Called from syscall package before Exec.
+//
+//go:linkname syscall_runtime_BeforeExec syscall.runtime_BeforeExec
+func syscall_runtime_BeforeExec() {}
+
+// Called from syscall package after Exec.
+//
+//go:linkname syscall_runtime_AfterExec syscall.runtime_AfterExec
+func syscall_runtime_AfterExec() {}

src/syscall/exec_unix.go

@@ -0,0 +1,7 @@
+//go:build unix
+
+package syscall
+
+// Implemented in runtime package.
+func runtime_BeforeExec()
+func runtime_AfterExec()

src/syscall/syscall.go

@@ -4,7 +4,7 @@ import (
 	"errors"
 	"sync/atomic"
 
-	"github.com/tinygo-org/tinygo/src/internal/bytealg"
+	"internal/bytealg"
 )
 
 const (