Fix cryptography build after emscripten update (#2683)

Makefile.envs

@@ -148,7 +148,7 @@ export STDLIB_MODULE_CFLAGS= $(SIDE_MODULE_CFLAGS) -I Include/ -I .
 # For RUST
 export CARGO_HOME ?= $(HOME)/.cargo
 export CARGO_BUILD_TARGET=wasm32-unknown-emscripten
-export CARGO_TARGET_WASM32_UNKNOWN_EMSCRIPTEN_LINKER=emcc
+export CARGO_TARGET_WASM32_UNKNOWN_EMSCRIPTEN_LINKER=$(PYODIDE_ROOT)/tools/rust_emcc_wrapper.py
 export PYO3_CONFIG_FILE=$(PYODIDE_ROOT)/tools/pyo3_config.ini
 
 # idealy we could automatically include all SIDE_MODULE_LDFLAGS here

emsdk/patches/0004-Disable-whole-archive-when-linking-rust.patch

@@ -1,33 +0,0 @@
-From c250eb29047c4341cdc1d13f3706eb6991cf0f9b Mon Sep 17 00:00:00 2001
-From: Hood Chatham <roberthoodchatham@gmail.com>
-Date: Thu, 6 Jan 2022 09:40:39 -0800
-Subject: [PATCH 4/4] Disable whole-archive when linking rust
-
-Rust .rlib archives contain an extra metadata file called lib.rmeta.
-Emscripten sets `--whole-archive` by default if LINKABLE is set.
-But with `--whole-archive` the linker crashes with an error due to
-the extra files. This disables the problematic `--whole-archive`
-setting when we are linking rust.
-
-See emscripten issue:
-https://github.com/emscripten-core/emscripten/issues/17109
----
- tools/building.py | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
-diff --git a/tools/building.py b/tools/building.py
-index 24ddaa13f..cb015e18f 100644
---- a/tools/building.py
-+++ b/tools/building.py
-@@ -360,7 +360,7 @@ def link_lld(args, target, external_symbols=None):
- 
-   # Emscripten currently expects linkable output (SIDE_MODULE/MAIN_MODULE) to
-   # include all archive contents.
--  if settings.LINKABLE:
-+  if settings.LINKABLE and not any(arg.endswith(".rlib") for arg in args):
-     args.insert(0, '--whole-archive')
-     args.append('--no-whole-archive')
- 
--- 
-2.25.1
-

packages/cryptography/meta.yaml

@@ -1,7 +1,6 @@
 package:
   name: cryptography
   version: 36.0.2
-  _disabled: true
 
 source:
   url: https://files.pythonhosted.org/packages/10/a7/51953e73828deef2b58ba1604de9167843ee9cd4185d8aaffcb45dd1932d/cryptography-36.0.2.tar.gz
@@ -25,6 +24,7 @@ build:
     $(OPENSSL_INCLUDE_PATH)
   ldflags: |
     $(OPENSSL_LIBRARY_PATH)
+    -Wl,--no-entry
 requirements:
   run:
     - openssl

tools/rust_emcc_wrapper.py

@@ -0,0 +1,45 @@
+#!/usr/bin/env python3
+import subprocess
+import sys
+
+
+def update_args(args):
+    # https://github.com/emscripten-core/emscripten/issues/17109
+    args.insert(0, "-Wl,--no-whole-archive")
+
+    # Remove -s ASSERTIONS=1
+    # See https://github.com/rust-lang/rust/pull/97928
+    for i in range(len(args)):
+        if "ASSERTIONS" in args[i]:
+            del args[i - 1 : i + 1]
+            break
+
+    # remove -lc. Not sure if it makes a difference but -lc doesn't belong here.
+    # https://github.com/emscripten-core/emscripten/issues/17191
+    for i in reversed(range(len(args))):
+        if args[i] == "c" and args[i - 1] == "-l":
+            del args[i - 1 : i + 1]
+
+    # Prevent a bunch of errors caused by buggy behavior in
+    # `esmcripten/tools/building.py:lld_flags_for_executable` REQUIRED_EXPORTS
+    # contains symbols that should come from the main module.
+    # https://github.com/emscripten-core/emscripten/issues/17202
+    args.append("-sERROR_ON_UNDEFINED_SYMBOLS=0")
+    # Seems like --no-entry should be implied by SIDE_MODULE but apparently it
+    # isn't?
+    args.append("-Wl,--no-entry")
+    # Without this, the dylink section seems to get deleted which causes trouble
+    # at load time.
+    args.append("-Wl,--no-gc-sections")
+
+    return args
+
+
+def main(args):
+    args = update_args(args)
+    return subprocess.call(["emcc"] + args)
+
+
+if __name__ == "__main__":
+    args = sys.argv[1:]
+    sys.exit(main(args))