Static sdk allow custom args (#3377)

Allow custom argument specification in the Static SDK workflow

### Motivation:

Sometimes users may want to specify more/different parameters such as
specifying building only some targets

### Modifications:

Add a parameter for the build arguments

### Result:

More flexible SDK CI.

You can see this in action here
https://github.com/apple/swift-nio/actions/runs/17858707940/job/50783709148?pr=3377

Author: rnro

.github/workflows/static_sdk.yml

@@ -7,6 +7,10 @@ on:
         type: string
         description: "Environment variables for jobs as JSON (e.g., '{\"DEBUG\":\"1\",\"LOG_LEVEL\":\"info\"}')."
         default: "{}"
+      command_arguments:
+        type: string
+        description: "The arguments passed to swift build. Defaults to '--swift-sdk x86_64-swift-linux-musl'."
+        default: "--swift-sdk x86_64-swift-linux-musl"
 
 jobs:
   construct-matrix:
@@ -42,7 +46,7 @@ jobs:
                 "image":"ubuntu:jammy",
                 "setup_command":"apt update -q && apt install -y -q curl jq tar && curl -s --retry 3 https://raw.githubusercontent.com/apple/swift-nio/main/scripts/install_swift_prerequisites.sh | bash && curl -s --retry 3 https://raw.githubusercontent.com/apple/swift-nio/main/scripts/install_static_sdk.sh | INSTALL_SWIFT_STATIC_SDK_VERSION=latest INSTALL_SWIFT_STATIC_SDK_ARCH=x86_64 bash && hash -r",
                 "command":"swift build",
-                "command_arguments":"--swift-sdk x86_64-swift-linux-musl",
+                "command_arguments":"${{ inputs.command_arguments }}",
                 "env":'"$env_vars_json"'
               },
               {
@@ -53,7 +57,7 @@ jobs:
                 "image":"ubuntu:jammy",
                 "setup_command":"apt update -q && apt install -y -q curl jq tar && curl -s --retry 3 https://raw.githubusercontent.com/apple/swift-nio/main/scripts/install_swift_prerequisites.sh | bash && curl -s --retry 3 https://raw.githubusercontent.com/apple/swift-nio/main/scripts/install_static_sdk.sh | INSTALL_SWIFT_STATIC_SDK_BRANCH=main INSTALL_SWIFT_STATIC_SDK_ARCH=x86_64 bash && hash -r",
                 "command":"swift build",
-                "command_arguments":"--swift-sdk x86_64-swift-linux-musl",
+                "command_arguments":"${{ inputs.command_arguments }}",
                 "env":'"$env_vars_json"'
               }
             ]