libc: Add strcoll()

libc/include/string.h

@@ -95,6 +95,9 @@ extern "C"
     /* Compare two fixed-size null-terminated strings, ignoring case. */
     int strncasecmp(const char* a, const char* b, size_t max);
 
+    /* Compare two null-terminated strings according to the current locale. */
+    int strcoll(const char* a, const char* b);
+
 #ifdef __cplusplus
 }
 #endif

libc/src/string.cpp

@@ -9,6 +9,12 @@ extern "C"
 
     extern "C++" const char* error_string(int);
 
+    int strcoll(const char* a, const char* b)
+    {
+        // In the POSIX or C locales strcoll() is equivalent to strcmp().
+        return strcmp(a, b);
+    }
+
     char* strerror(int errnum)
     {
         return const_cast<char*>(error_string(errnum));