frontend: fix stack protector option logic

Commit 97e23896a9168132b6d36ca22ae1af10dd53d80d regressed this behavior
because it made target_util.supportsStackProtector *correctly*
notice which zig backend is being used to generate code, while the
logic calling that function *incorrectly assumed* that .zig code is being
compiled, when in reality it might be only C code being compiled.

This commit adjusts the option resolution logic for stack protector so
that it takes into account the zig backend only if there is a zig
compilation unit. A separate piece of logic checks whether clang
supports stack protector for a given target.

closes #18009
closes #18114
closes #18254

1 files changed, 12 insertions, 1 deletions

diff --git a/src/Package/Module.zig b/src/Package/Module.zig
index 94431856ac..f1e7091855 100644
--- a/src/Package/Module.zig
+++ b/src/Package/Module.zig
@@ -229,7 +229,18 @@ pub fn create(arena: Allocator, options: CreateOptions) !*Package.Module {
     };
 
     const stack_protector: u32 = sp: {
-        if (!target_util.supportsStackProtector(target, zig_backend)) {
+        const use_zig_backend = options.global.have_zcu or
+            (options.global.any_c_source_files and options.global.c_frontend == .aro);
+        if (use_zig_backend and !target_util.supportsStackProtector(target, zig_backend)) {
+            if (options.inherited.stack_protector) |x| {
+                if (x > 0) return error.StackProtectorUnsupportedByTarget;
+            }
+            break :sp 0;
+        }
+
+        if (options.global.any_c_source_files and options.global.c_frontend == .clang and
+            !target_util.clangSupportsStackProtector(target))
+        {
             if (options.inherited.stack_protector) |x| {
                 if (x > 0) return error.StackProtectorUnsupportedByTarget;
             }