Restructure building the C API

This commit introduces a wrapper crate which is now the new "real" C
API. The purpose of this change is to enable using LTO when building the
C API. Currently LTO is disabled because one of the crate types of the C
API is an "rlib" which means that it can't have LTO performed due to
rustc limitations. The solution here is to remove the "cdylib" and
"staticlib" crate types from the "wasmtime-c-api" crate and introduce a
new crate 'wasmtime-c-api-artfact' which wraps the previous crate and
reexports it.

This way LTO can be enabled when just building the artifacts and the use
case from bytecodealliance#6765 is still satisfied by having a crate that can be linked
to from Rust. Locally this reduces the size of the C API artifact for me
by nearly 1M.

Cargo.toml

@@ -101,7 +101,7 @@ members = [
   "cranelift/isle/islec",
   "cranelift/serde",
   "crates/bench-api",
-  "crates/c-api",
+  "crates/c-api/artifact",
   "crates/environ/fuzz",
   "crates/test-programs",
   "crates/wasi-preview1-component-adapter",

ci/build-release-artifacts.sh

@@ -37,4 +37,4 @@ else
 fi
 
 cargo build --release $flags --target $target -p wasmtime-cli $bin_flags
-cargo build --release $flags --target $target -p wasmtime-c-api
+cargo build --release $flags --target $target -p wasmtime-c-api-artifact

crates/c-api/Cargo.toml

@@ -10,8 +10,6 @@ edition.workspace = true
 publish = false
 
 [lib]
-name = "wasmtime"
-crate-type = ["staticlib", "cdylib", "rlib"]
 doc = false
 test = false
 doctest = false
@@ -38,16 +36,6 @@ wasi-common = { workspace = true, optional = true }
 futures = { workspace = true, optional = true }
 
 [features]
-default = [
-  'profiling',
-  'wat',
-  'wasi',
-  'cache',
-  'parallel-compilation',
-  'async',
-  'coredump',
-  'addr2line',
-]
 async = ['wasmtime/async', 'futures']
 profiling = ["wasmtime/profiling"]
 cache = ["wasmtime/cache"]

crates/c-api/artifact/Cargo.toml

@@ -0,0 +1,42 @@
+[package]
+name = "wasmtime-c-api-artifact"
+version.workspace = true
+authors.workspace = true
+description = "C API to expose the Wasmtime runtime"
+license = "Apache-2.0 WITH LLVM-exception"
+repository = "https://github.com/bytecodealliance/wasmtime"
+readme = "README.md"
+edition.workspace = true
+publish = false
+
+[lib]
+name = "wasmtime"
+crate-type = ["staticlib", "cdylib"]
+doc = false
+test = false
+doctest = false
+
+[dependencies]
+wasmtime-c-api = { path = '..' }
+
+[features]
+default = [
+  'profiling',
+  'wat',
+  'wasi',
+  'cache',
+  'parallel-compilation',
+  'async',
+  'coredump',
+  'addr2line',
+]
+async = ['wasmtime-c-api/async']
+profiling = ["wasmtime-c-api/profiling"]
+cache = ["wasmtime-c-api/cache"]
+parallel-compilation = ['wasmtime-c-api/parallel-compilation']
+wasi = ['wasmtime-c-api/wasi']
+logging = ['wasmtime-c-api/logging']
+disable-logging = ["wasmtime-c-api/disable-logging"]
+coredump = ["wasmtime-c-api/coredump"]
+addr2line = ["wasmtime-c-api/addr2line"]
+wat = ["wasmtime-c-api/wat"]

crates/c-api/artifact/src/lib.rs

@@ -0,0 +1 @@
+pub use wasmtime_c_api::*;