Honor purego build tag

and_amd64.go

@@ -1,3 +1,5 @@
+//go:build !purego
+
 package and
 
 func and(dst, a, b []byte) {

and_amd64.s

@@ -1,5 +1,7 @@
 // Code generated by command: go run src.go -out ../../and_amd64.s -stubs ../../and_stubs_amd64.go -pkg and. DO NOT EDIT.
 
+//go:build !purego
+
 #include "textflag.h"
 
 // func andAVX2(dst *byte, a *byte, b *byte, l uint64)

and_arm64.go

@@ -1,3 +1,5 @@
+//go:build !purego
+
 package and
 
 //go:noescape

detect_axv2_never.go

@@ -1,4 +1,4 @@
-//go:build !amd64
+//go:build !amd64 || purego
 
 package and
 

detect_axv2_runtime.go

@@ -1,4 +1,4 @@
-//go:build amd64 && !amd64.v3
+//go:build amd64 && !amd64.v3 && !purego
 
 package and
 

detect_popcnt_never.go

@@ -1,4 +1,4 @@
-//go:build !amd64
+//go:build !amd64 || purego
 
 package and
 

detect_popcnt_runtime.go

@@ -1,4 +1,4 @@
-//go:build amd64 && !amd64.v2
+//go:build amd64 && !amd64.v2 && !purego
 
 package and
 

fallback.go

@@ -1,4 +1,4 @@
-//go:build !amd64 && !arm64
+//go:build (!amd64 && !arm64) || purego
 
 package and
 

internal/asm/src.go

@@ -7,6 +7,8 @@ import (
 )
 
 func main() {
+	ConstraintExpr("!purego")
+
 	gen("and", VPAND, "Sets dst to the bitwise and of a and b")
 	gen("or", VPOR, "Sets dst to the bitwise or of a and b")
 	gen("andNot", VPANDN, "Sets dst to the bitwise and of not(a) and b")