libc: update kernel library references

lib/libc/malloc/CMakeLists.txt

@@ -31,4 +31,4 @@ sysroot_add_library(
 	LIB_DIR /usr/lib)
 
 target_compile_definitions(libc-malloc PRIVATE ENABLE_GLOBAL_HEAP=1)
-target_link_libraries(libc-malloc libc-core libmango)
+target_link_libraries(libc-malloc libc-core libmagenta)

lib/libc/malloc/heap.c

@@ -1,11 +1,11 @@
 #include "liballoc.h"
 
 #include <heap/heap.h>
-#include <mango/handle.h>
-#include <mango/log.h>
-#include <mango/status.h>
-#include <mango/task.h>
-#include <mango/vm.h>
+#include <magenta/handle.h>
+#include <magenta/log.h>
+#include <magenta/status.h>
+#include <magenta/task.h>
+#include <magenta/vm.h>
 #include <stdio.h>
 
 #define HEAP_REGION_SIZE      0x40000000

lib/libc/malloc/include/heap/heap.h

@@ -2,7 +2,7 @@
 #define HEAP_H_
 
 #include <heap/_liballoc.h>
-#include <mango/types.h>
+#include <magenta/types.h>
 #include <stddef.h>
 
 typedef enum heap_result {