Disable loplugin:casttovoid when --disable-assert-always-abort

...as finding uses of variables in arguments to expand-to-nothing assert macros
is just not implemented not implemented.

Change-Id: Iacb3bd25d03eca13ac8ff3942f98e46dee3286b9
Reviewed-on: https://gerrit.libreoffice.org/47200Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

compilerplugins/clang/casttovoid.cxx

@@ -336,6 +336,9 @@ private:
     std::stack<QualType> returnTypes_;
 
     void run() override {
+        if (compiler.getPreprocessor().getIdentifierInfo("NDEBUG")->hasMacroDefinition()) {
+            return;
+        }
         if (!TraverseDecl(compiler.getASTContext().getTranslationUnitDecl())) {
             return;
         }

compilerplugins/clang/test/casttovoid.cxx

@@ -7,6 +7,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#undef NDEBUG
 #include <cassert>
 
 #define CAST_N3 (void) n3