gh-111046: for wasi-threads, export memory as well via the linker (GH-111099)

Author: yamt

Misc/NEWS.d/next/Build/2023-10-20-15-29-31.gh-issue-111046.2DxQl8.rst

@@ -0,0 +1 @@
+For wasi-threads, memory is now exported to fix compatibility issues with some wasm runtimes.

configure

@@ -2162,10 +2162,15 @@ AS_CASE([$ac_sys_system],
       # without this, configure fails to find pthread_create, sem_init,
       # etc because they are only available in the sysroot for
       # wasm32-wasi-threads.
+      # Note: wasi-threads requires --import-memory.
+      # Note: wasi requires --export-memory.
+      # Note: --export-memory is implicit unless --import-memory is given
+      # Note: this requires LLVM >= 16.
       AS_VAR_APPEND([CFLAGS], [" -target wasm32-wasi-threads -pthread"])
       AS_VAR_APPEND([CFLAGS_NODIST], [" -target wasm32-wasi-threads -pthread"])
       AS_VAR_APPEND([LDFLAGS_NODIST], [" -target wasm32-wasi-threads -pthread"])
       AS_VAR_APPEND([LDFLAGS_NODIST], [" -Wl,--import-memory"])
+      AS_VAR_APPEND([LDFLAGS_NODIST], [" -Wl,--export-memory"])
       AS_VAR_APPEND([LDFLAGS_NODIST], [" -Wl,--max-memory=10485760"])
     ])