Replace unsecure _splitpath by secure _splitpath_s

Use the predefined macros for the lengths of drive, dir and path.
This avoids potential buffer overruns.
Show also an error message in case of a too long path.

Signed-off-by: Noah Metzger <noah.metzger@bib.uni-mannheim.de>

ccutil/mainblk.cpp

@@ -64,12 +64,17 @@ void CCUtil::main_setup(const char *argv0, const char *basename) {
 #if defined(_WIN32)
   } else if (datadir == NULL || access(datadir.string(), 0) != 0) {
     /* Look for tessdata in directory of executable. */
-    static char drive[4];
-    static char dir[128];
-    static char exe[128];
-    DWORD length = GetModuleFileName(NULL, exe, sizeof(exe));
-    if (length > 0 && length < sizeof(exe)) {
-      _splitpath(exe, drive, dir, NULL, NULL);
+    char drive[_MAX_DRIVE];
+    char dir[_MAX_DIR];
+    char path[_MAX_PATH];
+    DWORD length = GetModuleFileName(NULL, path, sizeof(path));
+    if (length > 0 && length < sizeof(path)) {
+      errno_t result = _splitpath_s(path, drive, sizeof(drive),
+                                    dir, sizeof(dir), NULL, 0, NULL, 0);
+      if (result == ERANGE) {
+        tprintf("Error: Path too long: %s\n", path);
+      }
+
       datadir = drive;
       datadir += dir;
     }