digitalbitbox: fix build after #41902

This package depends on qtmultimedia which depends on libpulse whose libtool
files add `-lcap` to the linker command line. These libtool files should be
stripped with pruneLibtoolFiles, and then libcap dependency can be removed.

pkgs/applications/misc/digitalbitbox/default.nix

@@ -3,6 +3,7 @@
 , curl
 , fetchFromGitHub
 , git
+, libcap
 , libevent
 , libtool
 , libqrencode
@@ -67,6 +68,8 @@ in stdenv.mkDerivation rec {
   ];
 
   buildInputs = with stdenv.lib; [
+    # TODO: remove libcap when pruneLibtoolFiles applies to pulseaudio.
+    libcap
     libevent
     libtool
     libudev
@@ -112,6 +115,8 @@ in stdenv.mkDerivation rec {
     ${copyUdevRuleToOutput "52-hid-digitalbox.rules" udevRule52}
   '';
 
+  enableParallelBuilding = true;
+
   meta = with stdenv.lib; {
     description = "A QT based application for the Digital Bitbox hardware wallet";
     longDescription = ''