Shrink C API release artifacts (#11483) (#11484)

This is needed to currently shrink our `*.a` artifacts under 100M in
size which is required downstream in the wasmtime-go embedding. Some
testing in #11475 of using full LTO or only building Linux/macOS with 1
CGU shows that this'll likely increase cycle time by ~1 minute. Windows
builders are already the slowest release build builders and this is
adding 1 minute using 1 CGU vs 2-3 extra minutes for full LTO.
Linux/macOS are switched to using full LTO which the CI builders
currently have plenty of time for.

This shaves 50M off the C API artifacts for Linux which buys a good
amount of headroom for future changes.

Closes #11476

Author: alexcrichton

RELEASES.md

@@ -1,6 +1,6 @@
 ## 36.0.1
 
-Released 2025-08-20.
+Released 2025-08-21.
 
 ### Added
 
@@ -9,6 +9,12 @@ Released 2025-08-20.
   release.
   [#11473](https://github.com/bytecodealliance/wasmtime/pull/11473)
 
+### Changed
+
+* Release artifacts for the C API are now smaller than the previous release to
+  assist with redistribution as-is.
+  [#11483](https://github.com/bytecodealliance/wasmtime/pull/11483)
+
 --------------------------------------------------------------------------------
 
 ## 36.0.0

ci/build-release-artifacts.sh

@@ -71,6 +71,21 @@ fi
 
 cargo build --release $flags --target $target -p wasmtime-cli $bin_flags --features run
 
+# Shrink the size of `*.a` artifacts without spending too much extra time in CI.
+# See #11476 for some more context. Here Windows builds achieve this with 1 CGU
+# which results in modest size gains, and other platforms use LTO to achieve
+# much more significant size gains. The reason the platforms are different is
+# that CI is extremely slow on Windows, almost 2x slower, so this is an attempt
+# to keep CI cycle time under control.
+case $build in
+  *-mingw* | *-windows*)
+    export CARGO_PROFILE_RELEASE_CODEGEN_UNITS=1
+    ;;
+  *)
+    export CARGO_PROFILE_RELEASE_LTO=true
+    ;;
+esac
+
 mkdir -p target/c-api-build
 cd target/c-api-build
 cmake \