fix typo in dynamic linker path file loading code

fortunately the memory corruption could not hurt anything, but it
prevented clearing the final newline and thus prevented the last path
element from working.

src/ldso/dynlink.c

@@ -481,7 +481,7 @@ static struct dso *load_library(const char *name)
 					if (getline(&sys_path, (size_t[1]){0}, f) > 0) {
 						size_t l = strlen(sys_path);
 						if (l && sys_path[l-1]=='\n')
-							sys_path[-1] = 0;
+							sys_path[l-1] = 0;
 					}
 					fclose(f);
 				}