user: implement mlibc as the libc, finally.

It's finally done..

Signed-off-by: kaguya <vpshinomiya@protonmail.com>

user/include/mlibc/options/internal/gcc-extra/cxxabi.cpp

@@ -0,0 +1,20 @@
+
+#include <bits/ensure.h>
+
+// The cxxabi needs operator delete for *deleting* destructors, i.e., destructors that
+// are called by delete expressions. We never use such expressions in mlibc.
+// Note that G++ complains if we make the operator hidden,
+// thus we use it's mangled name as a workaround.
+#if defined(__clang__)
+	extern "C" [[gnu::visibility("hidden")]] void _ZdlPv() { // operator delete (void *, size_t)
+		__ensure(!"operator delete called! delete expressions cannot be used in mlibc.");
+	}
+#endif
+
+extern "C" [[gnu::visibility("hidden")]] void _ZdlPvj() { // operator delete (void *, unsigned int)
+	__ensure(!"operator delete called! delete expressions cannot be used in mlibc.");
+}
+
+extern "C" [[gnu::visibility("hidden")]] void _ZdlPvm() { // operator delete (void *, size_t)
+	__ensure(!"operator delete called! delete expressions cannot be used in mlibc.");
+}