clang 3.5 adds some annoying warnings

p99/p99_compiler.h

@@ -1069,6 +1069,10 @@ P99_IF_COMPILER(GNU, GCC diagnostic ignored "-Wmissing-field-initializers")
 P99_IF_COMPILER(OPEN64, GCC diagnostic ignored "-Wmissing-braces")
 P99_IF_COMPILER(OPEN64, GCC diagnostic ignored "-Wmissing-field-initializers")
 
+/* clang warns about features that are completely ok. */
+P99_IF_COMPILER(CLANG, GCC diagnostic ignored "-Wnon-literal-null-conversion")
+P99_IF_COMPILER(CLANG, GCC diagnostic ignored "-Wswitch-bool")
+
 /**
  ** @def P99_WARN_INIT_PUSH
  ** @brief Switch bogus warnings about initializers off.