Fix GPI-2 and enable TAGASPI

The rdma-core driver.h include is no longer installed:

 56dd87acd2

So ibv_read_sysfs_file() is not defined. As the symbols is still
distributed, we simply add the missing prototype manually.

Similarly, the gaspi_size_t gaspi_get_system_mem() function is not
available from the gaspi public headers, so we define it in the
max_mem.c test.

Fixes: rarias/bscpkgs#7

flake.nix

@@ -13,12 +13,5 @@
       bscOverlay = import ./overlay.nix;
       overlays.default = self.bscOverlay;
       legacyPackages.x86_64-linux = pkgs;
-
-      # propagate nixpkgs lib, so we can do bscpkgs.lib
-      inherit (nixpkgs) lib;
-
-      hydraJobs = {
-        inherit (self.legacyPackages.x86_64-linux.bsc-ci) test packages;
-      };
     };
 }

overlay.nix

@@ -88,8 +88,6 @@ in bscPkgs // {
       };
     };
 
-    packages = filterAttrs (_: isDerivation) bscPkgs;
-
     pkgs = final.runCommand "ci-pkgs" { }
       "printf '%s\n' ${toString (collect isDerivation bscPkgs)} > $out";