[libc] Add enough stubs to support new LLVM 16 sysroot

time.h and wctype.h had "#error not yet implemented" in them. Now time.h is correct (though the functions
are only declared), and wctype.h exists enough to define its types. Also a dlsym stub was added that just
returns 0.

src/libraries/libc/arch/amd64/libdl.cpp

@@ -4,4 +4,5 @@ extern "C" {
     // we have a real libdl
     int dladdr(const void *, void *) { return 0; }
     int dl_iterate_phdr(void *, void *) { return 0; }
+    int dlsym(void *, const char *) { return 0; }
 }

src/libraries/libc/include/time.h

@@ -10,4 +10,43 @@
   * file, You can obtain one at https://mozilla.org/MPL/2.0/.
   */
 
-#error time.h is not yet implemented.
+#include <__j6libc/null.h>
+#include <__j6libc/size_t.h>
+#include <stdint.h>
+
+#define CLOCKS_PER_SEC 1
+#define TIME_UTC 0
+
+typedef int64_t clock_t;
+typedef int64_t time_t;
+
+struct timespec
+{
+    time_t tv_sec;
+    long tv_nsec;
+};
+
+struct tm
+{
+    int tm_sec;
+    int tm_min;
+    int tm_hour;
+    int tm_mday;
+    int tm_mon;
+    int tm_year;
+    int tm_wday;
+    int tm_yday;
+    int tm_isdst;
+};
+
+clock_t clock(void);
+double difftime(time_t t1, time_t t0);
+time_t mktime(struct tm *timeptr);
+time_t time(time_t *timer);
+int timespec_get(struct timespec *ts, int base);
+
+char *asctime(const struct tm *timeptr);
+char *ctime(const time_t *timer);
+struct tm *gmtime(const time_t *timer);
+struct tm *localtime(const time_t *timer);
+size_t strftime(char *s, size_t maxsize, const char *fmt, const struct tm *timeptr);

src/libraries/libc/include/wchar.h

@@ -17,10 +17,6 @@
 #include <__j6libc/wchar_t.h>
 #include <stdarg.h>
 
-typedef unsigned int wint_t;
-
-#define WEOF  ((wint_t)-1)
-
 struct tm;
 
 typedef struct {

src/libraries/libc/include/wctype.h

@@ -10,4 +10,7 @@
   * file, You can obtain one at https://mozilla.org/MPL/2.0/.
   */
 
-#error wctype.h is not yet implemented.
+#include <__j6libc/wchar_t.h>
+
+typedef int wctrans_t;
+typedef int wctype_t;

src/libraries/libc/stdlib/dlmalloc.cpp

@@ -5420,6 +5420,8 @@ void* dlrealloc_in_place(void* oldmem, size_t bytes) {
     return mem;
 }
 
+void* aligned_alloc(size_t alignment, size_t size) { return dlmemalign(alignment, size); }
+
 void* dlmemalign(size_t alignment, size_t bytes) {
     if (alignment <= MALLOC_ALIGNMENT) {
         return dlmalloc(bytes);

src/libraries/libc_free/include/__j6libc/wchar_t.h

@@ -14,5 +14,9 @@
 typedef __WCHAR_TYPE__   wchar_t;
 #endif
 
+typedef unsigned int wint_t;
+
+#define WEOF  ((wint_t)-1)
+
 #define WCHAR_MAX  __WCHAR_MAX__
 #define WCHAR_MIN  ((-__WCHAR_MAX__) - 1)