include: zephyr: toolchain: Introduce macros to ignore -Wcast-qual

Allow enabling/disabling the -Wcast-qual warning, for example to cast away
constness.

Signed-off-by: Pieter De Gendt <[email protected]>

Author: pdgendt

include/zephyr/toolchain.h

@@ -246,6 +246,17 @@
 #define TOOLCHAIN_WARNING_UNUSED_VARIABLE
 #endif
 
+/**
+ * @def TOOLCHAIN_WARNING_CAST_QUAL
+ * @brief Toolchain-specific warning for pointer casts removing a type qualifier.
+ *
+ * Use this as an argument to the @ref TOOLCHAIN_DISABLE_WARNING and
+ * @ref TOOLCHAIN_ENABLE_WARNING family of macros.
+ */
+#ifndef TOOLCHAIN_WARNING_CAST_QUAL
+#define TOOLCHAIN_WARNING_CAST_QUAL
+#endif
+
 /**
  * @def TOOLCHAIN_DISABLE_WARNING
  * @brief Disable the specified compiler warning for all compilers.

include/zephyr/toolchain/gcc.h

@@ -684,6 +684,7 @@ do {                                                                    \
 #define TOOLCHAIN_WARNING_SHADOW                   "-Wshadow"
 #define TOOLCHAIN_WARNING_UNUSED_LABEL             "-Wunused-label"
 #define TOOLCHAIN_WARNING_UNUSED_VARIABLE          "-Wunused-variable"
+#define TOOLCHAIN_WARNING_CAST_QUAL                "-Wcast-qual"
 
 /* GCC-specific warnings that aren't in clang. */
 #if defined(__GNUC__) && !defined(__clang__)