diff --git a/src/core/ngx_string.c b/src/core/ngx_string.c
index d3ff368..fe6b1ee 100644
--- a/src/core/ngx_string.c
+++ b/src/core/ngx_string.c
@@ -853,6 +853,46 @@
 
 
 ngx_int_t
+ngx_filename_cmp(u_char *s1, u_char *s2, size_t n)
+{
+    ngx_uint_t  c1, c2;
+
+    while (n) {
+        c1 = (ngx_uint_t) *s1++;
+        c2 = (ngx_uint_t) *s2++;
+
+#if (NGX_HAVE_CASELESS_FILESYSTEM)
+        c1 = tolower(c1);
+        c2 = tolower(c2);
+#endif
+
+        if (c1 == c2) {
+
+            if (c1) {
+                n--;
+                continue;
+            }
+
+            return 0;
+        }
+
+        /* we need '/' to be the lowest character */
+
+        if (c1 == 0 || c2 == 0) {
+            return c1 - c2;
+        }
+
+        c1 = (c1 == '/') ? 0 : c1;
+        c2 = (c2 == '/') ? 0 : c2;
+
+        return c1 - c2;
+    }
+
+    return 0;
+}
+
+
+ngx_int_t
 ngx_atoi(u_char *line, size_t n)
 {
     ngx_int_t  value;
diff --git a/src/core/ngx_string.h b/src/core/ngx_string.h
index 92d246e..99bdbda 100644
--- a/src/core/ngx_string.h
+++ b/src/core/ngx_string.h
@@ -167,6 +167,7 @@
 ngx_int_t ngx_rstrncasecmp(u_char *s1, u_char *s2, size_t n);
 ngx_int_t ngx_memn2cmp(u_char *s1, u_char *s2, size_t n1, size_t n2);
 ngx_int_t ngx_dns_strcmp(u_char *s1, u_char *s2);
+ngx_int_t ngx_filename_cmp(u_char *s1, u_char *s2, size_t n);
 
 ngx_int_t ngx_atoi(u_char *line, size_t n);
 ngx_int_t ngx_atofp(u_char *line, size_t n, size_t point);
diff --git a/src/os/unix/ngx_darwin_config.h b/src/os/unix/ngx_darwin_config.h
index 149778c..7ac86c7 100644
--- a/src/os/unix/ngx_darwin_config.h
+++ b/src/os/unix/ngx_darwin_config.h
@@ -20,6 +20,7 @@
 #include <stddef.h>             /* offsetof() */
 #include <stdio.h>
 #include <stdlib.h>
+#include <ctype.h>
 #include <errno.h>
 #include <string.h>
 #include <signal.h>
diff --git a/src/os/unix/ngx_files.h b/src/os/unix/ngx_files.h
index df759df..4b20165 100644
--- a/src/os/unix/ngx_files.h
+++ b/src/os/unix/ngx_files.h
@@ -192,17 +192,6 @@
 void ngx_close_file_mapping(ngx_file_mapping_t *fm);
 
 
-#if (NGX_HAVE_CASELESS_FILESYSTEM)
-
-#define ngx_filename_cmp(s1, s2, n)  strncasecmp((char *) s1, (char *) s2, n)
-
-#else
-
-#define ngx_filename_cmp         ngx_memcmp
-
-#endif
-
-
 #define ngx_realpath(p, r)       (u_char *) realpath((char *) p, (char *) r)
 #define ngx_realpath_n           "realpath()"
 #define ngx_getcwd(buf, size)    (getcwd((char *) buf, size) != NULL)
diff --git a/src/os/unix/ngx_freebsd_config.h b/src/os/unix/ngx_freebsd_config.h
index 248e7a7..92b2928 100644
--- a/src/os/unix/ngx_freebsd_config.h
+++ b/src/os/unix/ngx_freebsd_config.h
@@ -16,6 +16,7 @@
 #include <stddef.h>             /* offsetof() */
 #include <stdio.h>
 #include <stdlib.h>
+#include <ctype.h>
 #include <errno.h>
 #include <string.h>
 #include <signal.h>
diff --git a/src/os/unix/ngx_linux_config.h b/src/os/unix/ngx_linux_config.h
index 8467a97..72594ba 100644
--- a/src/os/unix/ngx_linux_config.h
+++ b/src/os/unix/ngx_linux_config.h
@@ -22,6 +22,7 @@
 #include <stddef.h>             /* offsetof() */
 #include <stdio.h>
 #include <stdlib.h>
+#include <ctype.h>
 #include <errno.h>
 #include <string.h>
 #include <signal.h>
diff --git a/src/os/unix/ngx_posix_config.h b/src/os/unix/ngx_posix_config.h
index 4cf90cc..d725659 100644
--- a/src/os/unix/ngx_posix_config.h
+++ b/src/os/unix/ngx_posix_config.h
@@ -39,6 +39,7 @@
 #include <stddef.h>             /* offsetof() */
 #include <stdio.h>
 #include <stdlib.h>
+#include <ctype.h>
 #include <errno.h>
 #include <string.h>
 #include <signal.h>
diff --git a/src/os/unix/ngx_solaris_config.h b/src/os/unix/ngx_solaris_config.h
index e664ba8..ddfd984 100644
--- a/src/os/unix/ngx_solaris_config.h
+++ b/src/os/unix/ngx_solaris_config.h
@@ -22,6 +22,7 @@
 #include <stddef.h>             /* offsetof() */
 #include <stdio.h>
 #include <stdlib.h>
+#include <ctype.h>
 #include <errno.h>
 #include <string.h>
 #include <signal.h>
diff --git a/src/os/win32/ngx_files.h b/src/os/win32/ngx_files.h
index a462473..08e5dc6 100644
--- a/src/os/win32/ngx_files.h
+++ b/src/os/win32/ngx_files.h
@@ -172,11 +172,6 @@
 void ngx_close_file_mapping(ngx_file_mapping_t *fm);
 
 
-#define NGX_HAVE_CASELESS_FILESYSTEM  1
-
-#define ngx_filename_cmp(s1, s2, n) _strnicmp((char *) s1, (char *) s2, n)
-
-
 u_char *ngx_realpath(u_char *path, u_char *resolved);
 #define ngx_realpath_n              ""
 #define ngx_getcwd(buf, size)       GetCurrentDirectory(size, (char *) buf)
diff --git a/src/os/win32/ngx_win32_config.h b/src/os/win32/ngx_win32_config.h
index 67105f1..fcbb308 100644
--- a/src/os/win32/ngx_win32_config.h
+++ b/src/os/win32/ngx_win32_config.h
@@ -45,6 +45,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
+#include <ctype.h>
 #include <locale.h>
 
 #ifdef __WATCOMC__
@@ -123,7 +124,6 @@
 typedef __int32             int32_t;
 typedef unsigned __int16    uint16_t;
 #define ngx_libc_cdecl      __cdecl
-#define _strnicmp           strnicmp
 
 #else /* __WATCOMC__ */
 typedef unsigned int        uint32_t;
@@ -196,6 +196,10 @@
 #define NGX_HAVE_INHERITED_NONBLOCK  1
 #endif
 
+#ifndef NGX_HAVE_CASELESS_FILESYSTEM
+#define NGX_HAVE_CASELESS_FILESYSTEM  1
+#endif
+
 #ifndef NGX_HAVE_WIN32_TRANSMITPACKETS
 #define NGX_HAVE_WIN32_TRANSMITPACKETS  1
 #define NGX_HAVE_WIN32_TRANSMITFILE     0