LibC: Move mman.h to sys/mman.h

POSIX mandates that it is placed there.

Tests/Kernel/fuzz-syscalls.cpp

@@ -10,11 +10,11 @@
 #include <AK/StringBuilder.h>
 #include <AK/Vector.h>
 #include <errno.h>
-#include <mman.h>
 #include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/mman.h>
 #include <syscall.h>
 
 static bool is_deadly_syscall(int fn)

Tests/LibC/TestLibCMkTemp.cpp

@@ -9,10 +9,10 @@
 #include <LibCore/File.h>
 #include <LibTest/TestCase.h>
 #include <fcntl.h>
-#include <mman.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/mman.h>
 #include <sys/wait.h>
 #include <unistd.h>
 

Tests/UserspaceEmulator/write-oob.cpp

@@ -6,10 +6,10 @@
 
 #include <AK/Assertions.h>
 #include <LibCore/ArgsParser.h>
-#include <mman.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/mman.h>
 
 static void write8(void* ptr) { *(volatile uint8_t*)ptr = 1; }
 static void write16(void* ptr) { *(volatile uint16_t*)ptr = 1; }