Moving to glibc-fb

Summary:
It looks like we might have some trouble when building the new release with 4.8, since fbcode is using glibc2.17-fb by default and we are using glibc2.17. It was reported by Benjamin Renard in our internal group.

This diff moves our fbcode build to use glibc2.17-fb by default. I got some linker errors when compiling, complaining that `google::SetUsageMessage()` was undefined. After deleting all offending lines, the compile was successful and everything works.

Test Plan:
Compiled
Ran ./db_bench ./db_stress ./db_repl_stress

Reviewers: kailiu

Reviewed By: kailiu

CC: leveldb

Differential Revision: https://reviews.facebook.net/D15405

tools/db_repl_stress.cc

@@ -87,9 +87,6 @@ DEFINE_uint64(wal_size_limit_MB, 10, "the wal size limit for the run"
               "(in MB)");
 
 int main(int argc, const char** argv) {
-  google::SetUsageMessage(std::string("\nUSAGE:\n") + std::string(argv[0]) +
-    " --num_inserts=<num_inserts> --wal_ttl_seconds=<WAL_ttl_seconds>" +
-    " --wal_size_limit_MB=<WAL_size_limit_MB>");
   google::ParseCommandLineFlags(&argc, const_cast<char***>(&argv), true);
 
   Env* env = Env::Default();

tools/db_stress.cc

@@ -1488,8 +1488,6 @@ class StressTest {
 
 
 int main(int argc, char** argv) {
-  google::SetUsageMessage(std::string("\nUSAGE:\n") + std::string(argv[0]) +
-                          " [OPTIONS]...");
   google::ParseCommandLineFlags(&argc, &argv, true);
 
   if (FLAGS_statistics) {