Add getgrgid_r/getgrnam_r.

Bug: 22568551
Change-Id: I3c0772d119d6041063c6be53f5bcc5ea1768f0d5
diff --git a/libc/libc.map b/libc/libc.map
index 47c52a4..ffbd29c 100644
--- a/libc/libc.map
+++ b/libc/libc.map
@@ -1332,6 +1332,12 @@
     *;
 };
 
+LIBC_N {
+  global:
+    getgrgid_r;
+    getgrnam_r;
+} LIBC;
+
 LIBC_PRIVATE {
   global:
     ___Unwind_Backtrace; # arm
@@ -1453,4 +1459,4 @@
     SHA1Init; # arm x86 mips
     SHA1Transform; # arm x86 mips
     SHA1Update; # arm x86 mips
-} LIBC;
+} LIBC_N;