Canonicalize the path used by sh.

With a bunch of LibC work to support the feature. LibC now initializes
AK::StringImpl by default. It's now fine to use AK in LibC/Userland! :^)

AK/Assertions.h

@@ -1,8 +1,12 @@
 #pragma once
 
 #ifdef SERENITY
+#ifdef KERNEL
 #include <Kernel/kassert.h>
 #else
+#include <LibC/assert.h>
+#endif
+#else
 #include <assert.h>
 #define ASSERT(x) assert(x)
 #define ASSERT_NOT_REACHED() assert(false)

AK/StdLib.h

@@ -1,8 +1,13 @@
 #pragma once
 
 #ifdef SERENITY
+#ifdef KERNEL
 #include <Kernel/StdLib.h>
 #else
+#include <LibC/stdlib.h>
+#include <LibC/string.h>
+#endif
+#else
 #include <cstring>
 #include <cstdlib>
 #include <utility>

AK/kmalloc.h

@@ -3,10 +3,52 @@
 #include "Compiler.h"
 
 #ifdef SERENITY
-#ifdef USERLAND
-#include <LibC/stdlib.h>
-#else
+#ifdef KERNEL
 #include <Kernel/kmalloc.h>
+#else
+#include <LibC/stdlib.h>
+
+extern "C" {
+
+void* kcalloc(size_t nmemb, size_t size);
+void* kmalloc(size_t size) MALLOC_ATTR;
+void kfree(void* ptr);
+void* krealloc(void* ptr, size_t size);
+
+}
+
+inline void* operator new(size_t size)
+{
+    return kmalloc(size);
+}
+
+inline void* operator new[](size_t size)
+{
+    return kmalloc(size);
+}
+
+inline void operator delete(void* ptr)
+{
+    return kfree(ptr);
+}
+
+inline void operator delete[](void* ptr)
+{
+    return kfree(ptr);
+}
+
+inline void operator delete(void* ptr, size_t)
+{
+    return kfree(ptr);
+}
+
+inline void operator delete[](void* ptr, size_t)
+{
+    return kfree(ptr);
+}
+
+inline void* operator new(size_t, void* p) { return p; }
+inline void* operator new[](size_t, void* p) { return p; }
 #endif
 #else
 #include <new>