Add needed functions to glibc-compat for pkg

ports/glibc-compat/src/flock.c

+/*
+ * Copyright (c) 1995, 1996, 1997 Kungliga Tekniska Högskolan
+ * (Royal Institute of Technology, Stockholm, Sweden).
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of the Institute nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+
+#define OP_MASK (LOCK_SH | LOCK_EX | LOCK_UN)
+
+int flock(int fd, int operation)
+{
+  struct flock arg;
+  int code, cmd;
+
+  arg.l_whence = SEEK_SET;
+  arg.l_start = 0;
+  arg.l_len = 0;                /* means to EOF */
+
+  if (operation & LOCK_NB)
+    cmd = F_SETLK;
+  else
+    cmd = F_SETLKW;             /* Blocking */
+
+  switch (operation & OP_MASK) {
+  case LOCK_UN:
+    arg.l_type = F_UNLCK;
+    code = fcntl(fd, F_SETLK, &arg);
+    break;
+  case LOCK_SH:
+    arg.l_type = F_RDLCK;
+    code = fcntl(fd, cmd, &arg);
+    break;
+  case LOCK_EX:
+    arg.l_type = F_WRLCK;
+    code = fcntl(fd, cmd, &arg);
+    break;
+  default:
+    errno = EINVAL;
+    code = -1;
+    break;
+  }
+  return code;
+}