Enforce single module compilation for static libraries to make constructors run properly.

releasenotes.md

@@ -28,6 +28,7 @@
 - Contracts on generic modules would evaluate too late, sometimes not catching the error until it already occurred elsewhere.
 - Fix bug preventing optionals from being used in ranges or as indices.
 - Crash compiling for arm64 when returning 16 byte and smaller structs by value not a power of 2 #1649.
+- Enforce single module compilation for static libraries to make constructors run properly.
 
 ### Stdlib changes
 - Add `io::MultiReader`, `io::MultiWriter`, and `io::TeeReader` structs.

src/build/builder.c

@@ -297,6 +297,7 @@ static void update_build_target_from_options(BuildTarget *target, BuildOptions *
 			break;
 		case COMMAND_STATIC_LIB:
 			target->type = TARGET_TYPE_STATIC_LIB;
+			target->single_module = true;
 			break;
 		default:
 			target->run_after_compile = false;