diff --git a/backend/azureblob/azureblob.go b/backend/azureblob/azureblob.go
index 0ef8aaa34..635620b61 100644
--- a/backend/azureblob/azureblob.go
+++ b/backend/azureblob/azureblob.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !solaris && !js
+//go:build !plan9 && !solaris && !js && !wasm
 
 // Package azureblob provides an interface to the Microsoft Azure blob object storage system
 package azureblob
diff --git a/backend/azureblob/azureblob_internal_test.go b/backend/azureblob/azureblob_internal_test.go
index 67669775d..0a8132fb3 100644
--- a/backend/azureblob/azureblob_internal_test.go
+++ b/backend/azureblob/azureblob_internal_test.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !solaris && !js
+//go:build !plan9 && !solaris && !js && !wasm
 
 package azureblob
 
diff --git a/backend/azureblob/azureblob_test.go b/backend/azureblob/azureblob_test.go
index 6f2b65acf..68d15eecf 100644
--- a/backend/azureblob/azureblob_test.go
+++ b/backend/azureblob/azureblob_test.go
@@ -1,6 +1,6 @@
 // Test AzureBlob filesystem interface
 
-//go:build !plan9 && !solaris && !js
+//go:build !plan9 && !solaris && !js && !wasm
 
 package azureblob
 
diff --git a/backend/azureblob/azureblob_unsupported.go b/backend/azureblob/azureblob_unsupported.go
index 50fcea34c..6d39dcdd8 100644
--- a/backend/azureblob/azureblob_unsupported.go
+++ b/backend/azureblob/azureblob_unsupported.go
@@ -1,7 +1,7 @@
 // Build for azureblob for unsupported platforms to stop go complaining
 // about "no buildable Go source files "
 
-//go:build plan9 || solaris || js
+//go:build plan9 || solaris || js || wasm
 
 // Package azureblob provides an interface to the Microsoft Azure blob object storage system
 package azureblob
diff --git a/backend/azurefiles/azurefiles.go b/backend/azurefiles/azurefiles.go
index cb9dd2793..05149ebf5 100644
--- a/backend/azurefiles/azurefiles.go
+++ b/backend/azurefiles/azurefiles.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !js
+//go:build !plan9 && !js && !wasm
 
 // Package azurefiles provides an interface to Microsoft Azure Files
 package azurefiles
diff --git a/backend/azurefiles/azurefiles_internal_test.go b/backend/azurefiles/azurefiles_internal_test.go
index 4996267a1..81e0f7b1d 100644
--- a/backend/azurefiles/azurefiles_internal_test.go
+++ b/backend/azurefiles/azurefiles_internal_test.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !js
+//go:build !plan9 && !js && !wasm
 
 package azurefiles
 
diff --git a/backend/azurefiles/azurefiles_test.go b/backend/azurefiles/azurefiles_test.go
index 987d08494..79d82bd77 100644
--- a/backend/azurefiles/azurefiles_test.go
+++ b/backend/azurefiles/azurefiles_test.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !js
+//go:build !plan9 && !js && !wasm
 
 package azurefiles
 
diff --git a/backend/azurefiles/azurefiles_unsupported.go b/backend/azurefiles/azurefiles_unsupported.go
index d2723e62f..8d9059f8a 100644
--- a/backend/azurefiles/azurefiles_unsupported.go
+++ b/backend/azurefiles/azurefiles_unsupported.go
@@ -1,7 +1,7 @@
 // Build for azurefiles for unsupported platforms to stop go complaining
 // about "no buildable Go source files "
 
-//go:build plan9 || js
+//go:build plan9 || js || wasm
 
 // Package azurefiles provides an interface to Microsoft Azure Files
 package azurefiles
diff --git a/backend/cache/cache.go b/backend/cache/cache.go
index 6977ff2d7..f1c1a239e 100644
--- a/backend/cache/cache.go
+++ b/backend/cache/cache.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !js
+//go:build !plan9 && !js && !wasm
 
 // Package cache implements a virtual provider to cache existing remotes.
 package cache
diff --git a/backend/cache/cache_internal_test.go b/backend/cache/cache_internal_test.go
index 0138d8d83..facaa406e 100644
--- a/backend/cache/cache_internal_test.go
+++ b/backend/cache/cache_internal_test.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !js && !race
+//go:build !plan9 && !js && !race && !wasm
 
 package cache_test
 
diff --git a/backend/cache/cache_test.go b/backend/cache/cache_test.go
index 96b7e36ae..a34377418 100644
--- a/backend/cache/cache_test.go
+++ b/backend/cache/cache_test.go
@@ -1,6 +1,6 @@
 // Test Cache filesystem interface
 
-//go:build !plan9 && !js && !race
+//go:build !plan9 && !js && !race && !wasm
 
 package cache_test
 
diff --git a/backend/cache/cache_unsupported.go b/backend/cache/cache_unsupported.go
index 8c94aaf26..86c0e4866 100644
--- a/backend/cache/cache_unsupported.go
+++ b/backend/cache/cache_unsupported.go
@@ -1,7 +1,7 @@
 // Build for cache for unsupported platforms to stop go complaining
 // about "no buildable Go source files "
 
-//go:build plan9 || js
+//go:build plan9 || js || wasm
 
 // Package cache implements a virtual provider to cache existing remotes.
 package cache
diff --git a/backend/cache/cache_upload_test.go b/backend/cache/cache_upload_test.go
index a47a1792a..1e8096858 100644
--- a/backend/cache/cache_upload_test.go
+++ b/backend/cache/cache_upload_test.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !js && !race
+//go:build !plan9 && !js && !race && !wasm
 
 package cache_test
 
diff --git a/backend/cache/directory.go b/backend/cache/directory.go
index 5c45db9c7..1d341291b 100644
--- a/backend/cache/directory.go
+++ b/backend/cache/directory.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !js
+//go:build !plan9 && !js && !wasm
 
 package cache
 
diff --git a/backend/cache/handle.go b/backend/cache/handle.go
index c12080043..49165ca3a 100644
--- a/backend/cache/handle.go
+++ b/backend/cache/handle.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !js
+//go:build !plan9 && !js && !wasm
 
 package cache
 
diff --git a/backend/cache/object.go b/backend/cache/object.go
index 87c292804..8711b5831 100644
--- a/backend/cache/object.go
+++ b/backend/cache/object.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !js
+//go:build !plan9 && !js && !wasm
 
 package cache
 
diff --git a/backend/cache/plex.go b/backend/cache/plex.go
index ff686f793..18dfed012 100644
--- a/backend/cache/plex.go
+++ b/backend/cache/plex.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !js
+//go:build !plan9 && !js && !wasm
 
 package cache
 
diff --git a/backend/cache/storage_memory.go b/backend/cache/storage_memory.go
index 2b2acf8f4..3c45369e0 100644
--- a/backend/cache/storage_memory.go
+++ b/backend/cache/storage_memory.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !js
+//go:build !plan9 && !js && !wasm
 
 package cache
 
diff --git a/backend/cache/storage_persistent.go b/backend/cache/storage_persistent.go
index 737b2e4ae..7b395ea09 100644
--- a/backend/cache/storage_persistent.go
+++ b/backend/cache/storage_persistent.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !js
+//go:build !plan9 && !js && !wasm
 
 package cache
 
diff --git a/backend/cache/utils_test.go b/backend/cache/utils_test.go
index 9f85b0155..4f9998c93 100644
--- a/backend/cache/utils_test.go
+++ b/backend/cache/utils_test.go
@@ -1,5 +1,4 @@
-//go:build !plan9 && !js
-// +build !plan9,!js
+//go:build !plan9 && !js && !wasm
 
 package cache
 
diff --git a/backend/hasher/commands.go b/backend/hasher/commands.go
index 2797e5d4f..41585cdf3 100644
--- a/backend/hasher/commands.go
+++ b/backend/hasher/commands.go
@@ -1,3 +1,5 @@
+//go:build !js && !wasm
+
 package hasher
 
 import (
diff --git a/backend/hasher/hasher.go b/backend/hasher/hasher.go
index 1ee789eaf..8528f9cbd 100644
--- a/backend/hasher/hasher.go
+++ b/backend/hasher/hasher.go
@@ -1,3 +1,5 @@
+//go:build !js && !wasm
+
 // Package hasher implements a checksum handling overlay backend
 package hasher
 
diff --git a/backend/hasher/hasher_internal_test.go b/backend/hasher/hasher_internal_test.go
index e289d8f0d..77e8837a2 100644
--- a/backend/hasher/hasher_internal_test.go
+++ b/backend/hasher/hasher_internal_test.go
@@ -1,3 +1,5 @@
+//go:build !js && !wasm
+
 package hasher
 
 import (
diff --git a/backend/hasher/hasher_test.go b/backend/hasher/hasher_test.go
index f5119c724..d0e724b12 100644
--- a/backend/hasher/hasher_test.go
+++ b/backend/hasher/hasher_test.go
@@ -1,3 +1,5 @@
+//go:build !js && !wasm
+
 package hasher_test
 
 import (
diff --git a/backend/hasher/hasher_unsupported.go b/backend/hasher/hasher_unsupported.go
new file mode 100644
index 000000000..ca1edd208
--- /dev/null
+++ b/backend/hasher/hasher_unsupported.go
@@ -0,0 +1,7 @@
+// Build for hasher for unsupported platforms to stop go complaining
+// about "no buildable Go source files "
+
+//go:build plan9 || wasm
+
+// Package hasher provides a SFTP filesystem interface
+package hasher
diff --git a/backend/hasher/kv.go b/backend/hasher/kv.go
index c51c13b0e..c2d06e7bf 100644
--- a/backend/hasher/kv.go
+++ b/backend/hasher/kv.go
@@ -1,3 +1,5 @@
+//go:build !js && !wasm
+
 package hasher
 
 import (
diff --git a/backend/hasher/object.go b/backend/hasher/object.go
index 1003807c8..9d7958fc9 100644
--- a/backend/hasher/object.go
+++ b/backend/hasher/object.go
@@ -1,3 +1,5 @@
+//go:build !js && !wasm
+
 package hasher
 
 import (
diff --git a/backend/local/lchmod.go b/backend/local/lchmod.go
index 823718dfe..4a1004d3d 100644
--- a/backend/local/lchmod.go
+++ b/backend/local/lchmod.go
@@ -1,4 +1,4 @@
-//go:build windows || plan9 || js || linux
+//go:build windows || plan9 || js || linux || wasm
 
 package local
 
diff --git a/backend/local/lchmod_unix.go b/backend/local/lchmod_unix.go
index f1fdc4745..4e4de7941 100644
--- a/backend/local/lchmod_unix.go
+++ b/backend/local/lchmod_unix.go
@@ -1,4 +1,4 @@
-//go:build !windows && !plan9 && !js && !linux
+//go:build !windows && !plan9 && !js && !linux && !wasm
 
 package local
 
diff --git a/backend/local/lchtimes.go b/backend/local/lchtimes.go
index fcabdcc34..46fb3dc3b 100644
--- a/backend/local/lchtimes.go
+++ b/backend/local/lchtimes.go
@@ -1,4 +1,4 @@
-//go:build plan9 || js
+//go:build plan9 || js || wasm
 
 package local
 
diff --git a/backend/local/lchtimes_unix.go b/backend/local/lchtimes_unix.go
index 96889db47..59a37ba1a 100644
--- a/backend/local/lchtimes_unix.go
+++ b/backend/local/lchtimes_unix.go
@@ -1,4 +1,4 @@
-//go:build !windows && !plan9 && !js
+//go:build !windows && !plan9 && !js && !wasm
 
 package local
 
diff --git a/backend/local/metadata_other.go b/backend/local/metadata_other.go
index dc6a5a736..c7c9a97a9 100644
--- a/backend/local/metadata_other.go
+++ b/backend/local/metadata_other.go
@@ -1,4 +1,4 @@
-//go:build dragonfly || plan9 || js
+//go:build dragonfly || plan9 || js || wasm
 
 package local
 
diff --git a/backend/protondrive/protondrive.go b/backend/protondrive/protondrive.go
index 821e3f9c7..5b94e8c2c 100644
--- a/backend/protondrive/protondrive.go
+++ b/backend/protondrive/protondrive.go
@@ -1,3 +1,5 @@
+//go:build !js && !wasm
+
 // Package protondrive implements the Proton Drive backend
 package protondrive
 
diff --git a/backend/protondrive/protondrive_test.go b/backend/protondrive/protondrive_test.go
index 86aa0c075..ebec6df42 100644
--- a/backend/protondrive/protondrive_test.go
+++ b/backend/protondrive/protondrive_test.go
@@ -1,3 +1,5 @@
+//go:build !js && !wasm
+
 package protondrive_test
 
 import (
diff --git a/backend/protondrive/protondrive_unsupported.go b/backend/protondrive/protondrive_unsupported.go
new file mode 100644
index 000000000..5e4ccc087
--- /dev/null
+++ b/backend/protondrive/protondrive_unsupported.go
@@ -0,0 +1,7 @@
+// Build for protondrive for unsupported platforms to stop go complaining
+// about "no buildable Go source files "
+
+//go:build plan9 || wasm
+
+// Package protondrive provides a filesystem interface to Proton Drive
+package protondrive
diff --git a/backend/sftp/sftp.go b/backend/sftp/sftp.go
index 442881624..727e29d4c 100644
--- a/backend/sftp/sftp.go
+++ b/backend/sftp/sftp.go
@@ -1,4 +1,4 @@
-//go:build !plan9
+//go:build !plan9 && !wasm
 
 // Package sftp provides a filesystem interface using github.com/pkg/sftp
 package sftp
diff --git a/backend/sftp/sftp_internal_test.go b/backend/sftp/sftp_internal_test.go
index e799f6654..994a1f121 100644
--- a/backend/sftp/sftp_internal_test.go
+++ b/backend/sftp/sftp_internal_test.go
@@ -1,4 +1,4 @@
-//go:build !plan9
+//go:build !plan9 && !wasm
 
 package sftp
 
diff --git a/backend/sftp/sftp_test.go b/backend/sftp/sftp_test.go
index 2e9ad9f20..64a27e1ec 100644
--- a/backend/sftp/sftp_test.go
+++ b/backend/sftp/sftp_test.go
@@ -1,6 +1,6 @@
 // Test Sftp filesystem interface
 
-//go:build !plan9
+//go:build !plan9 && !wasm
 
 package sftp_test
 
diff --git a/backend/sftp/sftp_unsupported.go b/backend/sftp/sftp_unsupported.go
index 67794bc4f..b441913f9 100644
--- a/backend/sftp/sftp_unsupported.go
+++ b/backend/sftp/sftp_unsupported.go
@@ -1,7 +1,7 @@
 // Build for sftp for unsupported platforms to stop go complaining
 // about "no buildable Go source files "
 
-//go:build plan9
+//go:build plan9 || wasm
 
 // Package sftp provides a filesystem interface using github.com/pkg/sftp
 package sftp
diff --git a/backend/sftp/ssh.go b/backend/sftp/ssh.go
index d0a25e29e..e09677427 100644
--- a/backend/sftp/ssh.go
+++ b/backend/sftp/ssh.go
@@ -1,4 +1,4 @@
-//go:build !plan9
+//go:build !plan9 && !wasm
 
 package sftp
 
diff --git a/backend/sftp/ssh_external.go b/backend/sftp/ssh_external.go
index a42cdd7cc..c8032b1b1 100644
--- a/backend/sftp/ssh_external.go
+++ b/backend/sftp/ssh_external.go
@@ -1,4 +1,4 @@
-//go:build !plan9
+//go:build !plan9 && !wasm
 
 package sftp
 
diff --git a/backend/sftp/ssh_internal.go b/backend/sftp/ssh_internal.go
index 2508bbf31..84efa64c2 100644
--- a/backend/sftp/ssh_internal.go
+++ b/backend/sftp/ssh_internal.go
@@ -1,4 +1,4 @@
-//go:build !plan9
+//go:build !plan9 && !wasm
 
 package sftp
 
diff --git a/backend/sftp/stringlock.go b/backend/sftp/stringlock.go
index df658f961..d8933405b 100644
--- a/backend/sftp/stringlock.go
+++ b/backend/sftp/stringlock.go
@@ -1,4 +1,4 @@
-//go:build !plan9
+//go:build !plan9 && !wasm
 
 package sftp
 
diff --git a/backend/sftp/stringlock_test.go b/backend/sftp/stringlock_test.go
index ded8f3cfd..c279dc243 100644
--- a/backend/sftp/stringlock_test.go
+++ b/backend/sftp/stringlock_test.go
@@ -1,4 +1,4 @@
-//go:build !plan9
+//go:build !plan9 && !wasm
 
 package sftp
 
diff --git a/cmd/cachestats/cachestats.go b/cmd/cachestats/cachestats.go
index 115bbd534..ff93472df 100644
--- a/cmd/cachestats/cachestats.go
+++ b/cmd/cachestats/cachestats.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !js
+//go:build !plan9 && !js && !wasm
 
 // Package cachestats provides the cachestats command.
 package cachestats
diff --git a/cmd/cachestats/cachestats_unsupported.go b/cmd/cachestats/cachestats_unsupported.go
index 1ab469e91..d40f8a831 100644
--- a/cmd/cachestats/cachestats_unsupported.go
+++ b/cmd/cachestats/cachestats_unsupported.go
@@ -1,7 +1,7 @@
 // Build for cache for unsupported platforms to stop go complaining
 // about "no buildable Go source files "
 
-//go:build plan9 || js
+//go:build plan9 || js || wasm
 
 // Package cachestats provides the cachestats command.
 package cachestats
diff --git a/cmd/ncdu/ncdu.go b/cmd/ncdu/ncdu.go
index 41dbcd75a..17d8fd419 100644
--- a/cmd/ncdu/ncdu.go
+++ b/cmd/ncdu/ncdu.go
@@ -1,4 +1,4 @@
-//go:build !plan9 && !js
+//go:build !plan9 && !js && !wasm
 
 // Package ncdu implements a text based user interface for exploring a remote
 package ncdu
diff --git a/cmd/ncdu/ncdu_unsupported.go b/cmd/ncdu/ncdu_unsupported.go
index 34d99ed6c..2fda897d0 100644
--- a/cmd/ncdu/ncdu_unsupported.go
+++ b/cmd/ncdu/ncdu_unsupported.go
@@ -1,7 +1,7 @@
 // Build for ncdu for unsupported platforms to stop go complaining
 // about "no buildable Go source files "
 
-//go:build plan9 || js
+//go:build plan9 || js || wasm
 
 // Package ncdu implements a text based user interface for exploring a remote
 package ncdu
diff --git a/cmd/selfupdate/writable_unix.go b/cmd/selfupdate/writable_unix.go
index 48c355717..a24ffb45f 100644
--- a/cmd/selfupdate/writable_unix.go
+++ b/cmd/selfupdate/writable_unix.go
@@ -1,4 +1,4 @@
-//go:build !windows && !plan9 && !js && !noselfupdate
+//go:build !windows && !plan9 && !js && !noselfupdate && !wasm
 
 package selfupdate
 
diff --git a/cmd/selfupdate/writable_unsupported.go b/cmd/selfupdate/writable_unsupported.go
index 0f0380c01..6f271e855 100644
--- a/cmd/selfupdate/writable_unsupported.go
+++ b/cmd/selfupdate/writable_unsupported.go
@@ -1,4 +1,4 @@
-//go:build (plan9 || js) && !noselfupdate
+//go:build (plan9 || js || wasm) && !noselfupdate
 
 package selfupdate
 
diff --git a/cmd/serve/sftp/connection.go b/cmd/serve/sftp/connection.go
index 3fc4396cf..fc078f6d5 100644
--- a/cmd/serve/sftp/connection.go
+++ b/cmd/serve/sftp/connection.go
@@ -1,4 +1,4 @@
-//go:build !plan9
+//go:build !plan9 && !wasm
 
 package sftp
 
diff --git a/cmd/serve/sftp/connection_test.go b/cmd/serve/sftp/connection_test.go
index b406e79f4..36159bf94 100644
--- a/cmd/serve/sftp/connection_test.go
+++ b/cmd/serve/sftp/connection_test.go
@@ -1,4 +1,4 @@
-//go:build !plan9
+//go:build !plan9 && !wasm
 
 package sftp
 
diff --git a/cmd/serve/sftp/handler.go b/cmd/serve/sftp/handler.go
index f7c9c3c47..290bd69d6 100644
--- a/cmd/serve/sftp/handler.go
+++ b/cmd/serve/sftp/handler.go
@@ -1,4 +1,4 @@
-//go:build !plan9
+//go:build !plan9 && !wasm
 
 package sftp
 
diff --git a/cmd/serve/sftp/server.go b/cmd/serve/sftp/server.go
index 17889503d..1062cf69b 100644
--- a/cmd/serve/sftp/server.go
+++ b/cmd/serve/sftp/server.go
@@ -1,4 +1,4 @@
-//go:build !plan9
+//go:build !plan9 && !wasm
 
 package sftp
 
diff --git a/cmd/serve/sftp/sftp.go b/cmd/serve/sftp/sftp.go
index 4f641874c..de1a6d7ca 100644
--- a/cmd/serve/sftp/sftp.go
+++ b/cmd/serve/sftp/sftp.go
@@ -1,4 +1,4 @@
-//go:build !plan9
+//go:build !plan9 && !wasm
 
 // Package sftp implements an SFTP server to serve an rclone VFS
 package sftp
diff --git a/cmd/serve/sftp/sftp_test.go b/cmd/serve/sftp/sftp_test.go
index e18d6b86d..c4a5cea41 100644
--- a/cmd/serve/sftp/sftp_test.go
+++ b/cmd/serve/sftp/sftp_test.go
@@ -3,7 +3,7 @@
 //
 // We skip tests on platforms with troublesome character mappings
 
-//go:build !windows && !darwin && !plan9
+//go:build !windows && !darwin && !plan9 && !wasm
 
 package sftp
 
diff --git a/cmd/serve/sftp/sftp_unsupported.go b/cmd/serve/sftp/sftp_unsupported.go
index 22e0673a7..12dd8ca0e 100644
--- a/cmd/serve/sftp/sftp_unsupported.go
+++ b/cmd/serve/sftp/sftp_unsupported.go
@@ -1,7 +1,7 @@
 // Build for sftp for unsupported platforms to stop go complaining
 // about "no buildable Go source files "
 
-//go:build plan9
+//go:build plan9 || wasm
 
 // Package sftp implements an SFTP server to serve an rclone VFS
 package sftp
diff --git a/fs/fserrors/retriable_errors.go b/fs/fserrors/retriable_errors.go
index bd24f0a8e..a7d6f1914 100644
--- a/fs/fserrors/retriable_errors.go
+++ b/fs/fserrors/retriable_errors.go
@@ -1,4 +1,4 @@
-//go:build !plan9
+//go:build !plan9 && !wasm
 
 package fserrors
 
diff --git a/fs/log/redirect_stderr_unix.go b/fs/log/redirect_stderr_unix.go
index dd7aa4d6f..c3891b8e8 100644
--- a/fs/log/redirect_stderr_unix.go
+++ b/fs/log/redirect_stderr_unix.go
@@ -1,6 +1,6 @@
 // Log the panic under unix to the log file
 
-//go:build !windows && !solaris && !plan9 && !js
+//go:build !windows && !solaris && !plan9 && !js && !wasm
 
 package log
 
diff --git a/lib/diskusage/diskusage_unsupported.go b/lib/diskusage/diskusage_unsupported.go
index 1e4bddc40..11e1cb15d 100644
--- a/lib/diskusage/diskusage_unsupported.go
+++ b/lib/diskusage/diskusage_unsupported.go
@@ -1,4 +1,4 @@
-//go:build illumos || js || plan9 || solaris
+//go:build illumos || js || plan9 || solaris || wasm
 
 package diskusage
 
diff --git a/lib/mmap/mmap_unix.go b/lib/mmap/mmap_unix.go
index 8bc9e2e22..49637b9cf 100644
--- a/lib/mmap/mmap_unix.go
+++ b/lib/mmap/mmap_unix.go
@@ -1,7 +1,7 @@
 // Package mmap implements a large block memory allocator using
 // anonymous memory maps.
 
-//go:build !plan9 && !windows && !js
+//go:build !plan9 && !windows && !js && !wasm
 
 package mmap
 
diff --git a/lib/mmap/mmap_unsupported.go b/lib/mmap/mmap_unsupported.go
index e78817da7..25bbaaeaa 100644
--- a/lib/mmap/mmap_unsupported.go
+++ b/lib/mmap/mmap_unsupported.go
@@ -1,6 +1,6 @@
 // Fallback Alloc and Free for unsupported OSes
 
-//go:build plan9 || js
+//go:build plan9 || js || wasm
 
 package mmap