libc: Add a _POSIX_VERSION define

libc/include/stdlib.h

@@ -98,8 +98,13 @@ extern "C"
      * endptr if nonnull. */
     unsigned long strtoul(const char* str, char** endptr, int base);
 
-#define strtoll strtol
-#define strtoull strtoul
+    /* Parse an integer of the specified base from a string, storing the first non-number character in endptr if
+     * nonnull. */
+    long long strtoll(const char* str, char** endptr, int base);
+
+    /* Parse an unsigned integer of the specified base from a string, storing the first non-number character in
+     * endptr if nonnull. */
+    unsigned long long strtoull(const char* str, char** endptr, int base);
 
     /* Return the next pseudorandom number. */
     int rand();

libc/include/unistd.h

@@ -22,6 +22,7 @@
 #define _POSIX_SYNCHRONIZED_IO 200112L
 #define _POSIX_SAVED_IDS 200112L
 #define _POSIX_VDISABLE (-2)
+#define _POSIX_VERSION 200112L
 
 #ifdef __cplusplus
 extern "C"

libc/src/stdlib.cpp

@@ -101,6 +101,16 @@ extern "C"
         return rc;
     }
 
+    long long strtoll(const char* str, char** endptr, int base)
+    {
+        return strtol(str, endptr, base);
+    }
+
+    unsigned long long strtoull(const char* str, char** endptr, int base)
+    {
+        return strtoul(str, endptr, base);
+    }
+
     __noreturn void abort()
     {
         // First, try to unblock SIGABRT and then raise it.