Get rid of non-portable drand48. (#1349)

Summary: Pull Request resolved: https://github.com/facebookresearch/faiss/pull/1349

Reviewed By: mdouze

Differential Revision: D23289393

Pulled By: beauby

fbshipit-source-id: a626bbf252ced4ae01abbc3dce4be50d9e628728

tests/test_dealloc_invlists.cpp

@@ -10,6 +10,7 @@
 
 #include <memory>
 #include <vector>
+#include <random>
 
 #include <gtest/gtest.h>
 
@@ -19,6 +20,7 @@
 #include <faiss/index_io.h>
 #include <faiss/IVFlib.h>
 
+
 using namespace faiss;
 
 namespace {
@@ -38,12 +40,15 @@ size_t nb = 1000;
 // nb of queries
 size_t nq = 200;
 
+std::mt19937 rng;
 
 std::vector<float> make_data(size_t n)
 {
     std::vector <float> database (n * d);
+    std::uniform_real_distribution<> distrib;
+
     for (size_t i = 0; i < n * d; i++) {
-        database[i] = drand48();
+        database[i] = distrib(rng);
     }
     return database;
 }