qbs build: Suppress -Wparentheses-equality globally

This warning is very noisy and is triggered by Qt and libc headers.

Change-Id: I7aa2eaba7ab52e47fe3daf4bac5a0fe59a77f487
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

qbs/imports/QtcProduct.qbs

@@ -27,6 +27,11 @@ Product {
 
     Depends { name: "qtc" }
 
+    Properties {
+        condition: qbs.toolchain.includes("clang")
+        cpp.commonCompilerFlags: "-Wno-parentheses-equality"
+    }
+
     cpp.cxxFlags: {
         var flags = [];
         if (qbs.toolchain.contains("gcc")) {

src/libs/3rdparty/lua/lua.qbs

@@ -13,11 +13,6 @@ QtcLibrary {
         return defines;
     }
 
-    Properties {
-        condition: qbs.toolchain.includes("clang")
-        cpp.cFlags: "-Wno-parentheses-equality"
-    }
-
     Group {
         name: "Sources"
         prefix: "src/"