util/Manual: work around strict-aliasing warning

src/util/Manual.hxx

@@ -40,6 +40,11 @@
 
 #include <assert.h>
 
+#if defined(__clang__) || GCC_CHECK_VERSION(4,7)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstrict-aliasing"
+#endif
+
 /**
  * Container for an object that gets constructed and destructed
  * manually.  The object is constructed in-place, and therefore
@@ -108,4 +113,8 @@ public:
 	}
 };
 
+#if defined(__clang__) || GCC_VERSION >= 40700
+#pragma GCC diagnostic pop
+#endif
+
 #endif