Support gcc 4.9 in cmake, fix uninitialized value warnings

cmake_modules/TokuSetupCompiler.cmake

@@ -137,6 +137,14 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL Clang)
   set(CMAKE_C_FLAGS_RELEASE "-g -O3 ${CMAKE_C_FLAGS_RELEASE} -UNDEBUG")
   set(CMAKE_CXX_FLAGS_RELEASE "-g -O3 ${CMAKE_CXX_FLAGS_RELEASE} -UNDEBUG")
 else ()
+  if (CMAKE_CXX_COMPILER_ID MATCHES GNU)
+    ## Versions of gcc >= 4.9.0 require special version of 'ar' and 'ranlib' for
+    ## link-time optimizations to work properly.
+    if (NOT (CMAKE_CXX_COMPILER_VERSION VERSION_LESS "4.9.0"))
+      set(CMAKE_AR "gcc-ar")
+      set(CMAKE_RANLIB "gcc-ranlib")
+    endif()
+  endif()
   # we overwrite this because the default passes -DNDEBUG and we don't want that
   set(CMAKE_C_FLAGS_RELWITHDEBINFO "-flto -fuse-linker-plugin ${CMAKE_C_FLAGS_RELWITHDEBINFO} -g -O3 -UNDEBUG")
   set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "-flto -fuse-linker-plugin ${CMAKE_CXX_FLAGS_RELWITHDEBINFO} -g -O3 -UNDEBUG")

ft/log_upgrade.cc

@@ -321,8 +321,8 @@ toku_maybe_upgrade_log(const char *env_dir, const char *log_dir, LSN * lsn_of_cl
         r = 0; //Logs are up to date
     else {
         FOOTPRINT(4);
-        LSN last_lsn;
-        TXNID last_xid;
+        LSN last_lsn = ZERO_LSN;
+        TXNID last_xid = TXNID_NONE;
         r = verify_clean_shutdown_of_log_version(log_dir, version_of_logs_on_disk, &last_lsn, &last_xid);
         if (r != 0) {
             goto cleanup;

ft/logger.cc

@@ -621,7 +621,7 @@ int toku_logger_find_next_unused_log_file(const char *directory, long long *resu
     if (d==0) return get_error_errno();
     while ((de=readdir(d))) {
         if (de==0) return get_error_errno();
-        long long thisl;
+        long long thisl = -1;
         if ( is_a_logfile(de->d_name, &thisl) ) {
             if ((long long)thisl > maxf) maxf = thisl;
         }