test(e2e): 195 用诊断而不是 --strict 判定

`--strict` 会把**所有**降级提升为错误,包括与本测试无关的那些 —— Windows 上
clang 报「this toolchain and platform combination emits no GNU depfile」,于是
195 在 Windows 上因为一件它并不关心的事而红。

本测试要断言的是「没有任何谓词匹配的平台上,请求该 feature 不是未知 feature
错误」,那就直接断言那条诊断不出现。

Author: speak-agent

tests/e2e/195_target_cfg_feature_deps.sh

@@ -129,10 +129,19 @@ nomatchlib = { path = "../nomatch", features = ["codegen"] }
 EOF
 printf 'int main(){}\n' > nmapp/src/main.cpp
 cd nmapp
-"$MCPP" build --strict > b3.log 2>&1 || {
+# Asserted on the DIAGNOSTIC rather than with --strict: --strict promotes every
+# degradation, including unrelated ones (clang on Windows reports "this
+# toolchain and platform combination emits no GNU depfile"), so it would make
+# this test fail for a reason it is not about.
+"$MCPP" build > b3.log 2>&1 || {
     cat b3.log
     echo "FAIL: requesting a conditionally-populated feature failed where no predicate matches"
     exit 1
 }
+grep -q "does not declare requested feature" b3.log && {
+    cat b3.log
+    echo "FAIL: the feature was reported as undeclared where no predicate matches"
+    exit 1
+}
 
 echo "PASS: 195_target_cfg_feature_deps"