https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53431
--- Comment #13 from Jeffrey Walton <noloader at gmail dot com> --- This issued caused Crypto++ to remove -Wall (and above) under GCC. Crypto++ is C++ with lots of interfaces, and it performs a fair amount of intermediate calculations used in an assert. It really needed the following to work as expected: // GCC diagnostcs available after GCC 4.2 (https://gcc.gnu.org/ml/gcc-help/2015-07/msg00063.html) #define GCC_DIAGNOSTIC_AWARE ((__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 2)) || defined(__clang__)) #if GCC_DIAGNOSTIC_AWARE # pragma GCC diagnostic push # pragma GCC diagnostic ignored "-Wunused-value" # pragma GCC diagnostic ignored "-Wunused-variable" #endif Crypto++ is fortunate in that its multi-compiler friendly and cross-platform. It can use Clang, ICC, Comeau or, say MSVC with /W4. Other projects are not so lucky. They include Asterisk (the PBX software package). Asterisk uses trampolines, so it cannot compile under Clang. And it never supported MSVC.
