Fix adb "ptsname is not thread-safe; use ptsname_r instead" build break.

(cherry picked from commit d235288553f8c0535f51dfb8f05f81e1bc01e4ed)

Change-Id: I05f8160bc8c356cb8a57e2bc5677517750700456
diff --git a/adb/services.c b/adb/services.c
index 2875ce0..e61371a 100644
--- a/adb/services.c
+++ b/adb/services.c
@@ -206,7 +206,6 @@
     fprintf(stderr, "error: create_subproc_pty not implemented on Win32 (%s %s %s)\n", cmd, arg0, arg1);
     return -1;
 #else /* !HAVE_WIN32_PROC */
-    char *devname;
     int ptm;
 
     ptm = unix_open("/dev/ptmx", O_RDWR | O_CLOEXEC); // | O_NOCTTY);
@@ -215,8 +214,8 @@
         return -1;
     }
 
-    if(grantpt(ptm) || unlockpt(ptm) ||
-       ((devname = (char*) ptsname(ptm)) == 0)){
+    char devname[64];
+    if(grantpt(ptm) || unlockpt(ptm) || ptsname_r(ptm, devname, sizeof(devname)) != 0) {
         printf("[ trouble with /dev/ptmx - %s ]\n", strerror(errno));
         adb_close(ptm);
         return -1;