Everywhere: Remove string.h include from AK/Traits.h and resolve fallout

A lot of places were relying on AK/Traits.h to give it strnlen, memcmp,
memcpy and other related declarations.

In the quest to remove inclusion of LibC headers from Kernel files, deal
with all the fallout of this included-everywhere header including less
things.

AK/FuzzyMatch.cpp

@@ -6,6 +6,7 @@
 
 #include <AK/CharacterTypes.h>
 #include <AK/FuzzyMatch.h>
+#include <string.h>
 
 namespace AK {
 

AK/JsonObjectSerializer.h

@@ -84,11 +84,11 @@ public:
         TRY(begin_item(key));
         if constexpr (IsLegacyBuilder<Builder>) {
             TRY(m_builder.try_append('"'));
-            TRY(m_builder.try_append_escaped_for_json({ value, strlen(value) }));
+            TRY(m_builder.try_append_escaped_for_json({ value, __builtin_strlen(value) }));
             TRY(m_builder.try_append('"'));
         } else {
             TRY(m_builder.append('"'));
-            TRY(m_builder.append_escaped_for_json({ value, strlen(value) }));
+            TRY(m_builder.append_escaped_for_json({ value, __builtin_strlen(value) }));
             TRY(m_builder.append('"'));
         }
         return {};

AK/PrintfImplementation.h

@@ -10,10 +10,10 @@
 #include <AK/StdLibExtras.h>
 #include <AK/Types.h>
 #include <stdarg.h>
-#include <wchar.h>
 
 #ifndef KERNEL
 #    include <math.h>
+#    include <wchar.h>
 #endif
 
 #ifdef AK_OS_SERENITY

AK/StringUtils.cpp

@@ -14,9 +14,12 @@
 #include <AK/StringView.h>
 #include <AK/Vector.h>
 
-#ifndef KERNEL
+#ifdef KERNEL
+#    include <Kernel/StdLib.h>
+#else
 #    include <AK/DeprecatedString.h>
 #    include <AK/FloatingPointStringConversions.h>
+#    include <string.h>
 #endif
 
 namespace AK {

AK/Time.h

@@ -11,12 +11,11 @@
 #include <AK/Platform.h>
 #include <AK/Types.h>
 
-// Kernel and Userspace pull in the definitions from different places.
-// Avoid trying to figure out which one.
-struct timeval;
-struct timespec;
-
-#if defined(AK_OS_WINDOWS)
+#if defined(AK_OS_SERENITY) && defined(KERNEL)
+#    include <Kernel/API/POSIX/sys/time.h>
+#    include <Kernel/API/POSIX/time.h>
+#else
+#    include <sys/time.h>
 #    include <time.h>
 #endif
 

AK/Traits.h

@@ -11,7 +11,6 @@
 #include <AK/Forward.h>
 #include <AK/HashFunctions.h>
 #include <AK/StringHash.h>
-#include <string.h>
 
 namespace AK {