Implement multiple kind of workarounds for GCC 12

as it produces more false warnings

Include missing header in C++ mode

m-core.h

@@ -181,10 +181,18 @@
 
 #elif defined(__GNUC__)
 
+#if __GNUC__ >= 12
+/* Warnings disabled for GNU C in C mode (Wstringop-overflow produces false warnings) */
+#define M_BEGIN_PROTECTED_CODE                                                \
+  _Pragma("GCC diagnostic push")                                              \
+  _Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"")                   \
+  _Pragma("GCC diagnostic ignored \"-Wstringop-overflow\"")
+#else
 /* Warnings disabled for GNU C in C mode */
 #define M_BEGIN_PROTECTED_CODE                                                \
   _Pragma("GCC diagnostic push")                                              \
   _Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\"")
+#endif
 
 #define M_END_PROTECTED_CODE                                                  \
   _Pragma("GCC diagnostic pop")
@@ -2771,7 +2779,7 @@ namespace m_lib {
 #define M_CSTR(...)                                                           \
   (m_lib::m_char_array<M_USE_CSTR_ALLOC>(__VA_ARGS__)).m_get()
 
-#elif defined(__GNUC__) && !defined(M_ADDRESS_SANITIZER)
+#elif defined(__GNUC__) && !defined(M_ADDRESS_SANITIZER) && __GNUC__ < 12
 
 /* Return a constant string constructed based on the printf-liked formated string
    and its arguments.

m-funcobj.h

@@ -310,7 +310,9 @@
                                                                     )         \
                       )                                                       \
   {                                                                           \
-    struct M_C(name, _s) *self = (struct M_C(name, _s) *)(void*)_self;	       \
+    /* Let's go through an uintptr_t to avoid [broken] aliasing detection by compiler */ \
+    uintptr_t __self = (uintptr_t) _self;				      \
+    struct M_C(name, _s) *self = (struct M_C(name, _s) *)(void*)__self;       \
     (void) self; /* maybe unused */                                           \
     callback_core;                                                            \
   }                                                                           \

m-string.h

@@ -1632,7 +1632,8 @@ m_str1ng_utf8_decode(char c, m_str1ng_utf8_state_e *state,
   const unsigned int type = m_core_clz32((unsigned char)~c) - (unsigned) (sizeof(uint32_t) - 1) * CHAR_BIT;
   const m_string_unicode_t mask1 = (UINT32_MAX - (m_string_unicode_t)(*state != M_STR1NG_UTF8_STARTING) + 1);
   const m_string_unicode_t mask2 = (0xFFU >> type);
-  *unicode = ((*unicode << 6) & mask1) | ((unsigned int) c & mask2);
+  const m_string_unicode_t c1 = (m_string_unicode_t) c;
+  *unicode = ((*unicode << 6) & mask1) | (c1 & mask2);
   *state = (m_str1ng_utf8_state_e) M_STR1NG_UTF8_STATE_TAB[(unsigned int) *state + type];
 }
 

tests/test-marray.c

@@ -449,6 +449,8 @@ static void test_double(void)
 
 /* For this, we need new placement support */
 #include <new>
+/* For std::move */
+#include <utility>
 
 /* Some Simple Oplist for a C++ class (using new placement feature)
    Some features may not be always available (like comparison or I/O).