libvdpau: fix tracing feature (#355297)

pkgs/by-name/li/libvdpau/installdir.patch

@@ -1,9 +0,0 @@
---- a/trace/meson.build	2020-02-15 16:34:58.698832000 +0100
-+++ b/trace/meson.build	2020-02-15 16:39:05.359952802 +0100
-@@ -4,5 +4,5 @@
-     dependencies : libdl,
-     version : '1.0.0',
-     install : true,
--    install_dir : moduledir,
-+    install_dir : get_option('prefix') + '/lib/libvdpau',
- )

pkgs/by-name/li/libvdpau/package.nix

@@ -8,7 +8,7 @@ stdenv.mkDerivation rec {
     url = "https://gitlab.freedesktop.org/vdpau/libvdpau/-/archive/${version}/${pname}-${version}.tar.bz2";
     sha256 = "sha256-pdUKQrjCiP68BxUatkOsjeBqGERpZcckH4m06BCCGRM=";
   };
-  patches = [ ./installdir.patch ];
+  patches = [ ./tracing.patch ];
 
   outputs = [ "out" "dev" ];
 
@@ -21,6 +21,12 @@ stdenv.mkDerivation rec {
 
   NIX_LDFLAGS = lib.optionalString stdenv.hostPlatform.isDarwin "-lX11";
 
+  # The tracing library in this package must be conditionally loaded with dlopen().
+  # Therefore, we must restore the RPATH entry for the library itself that was removed by the patchelf hook.
+  postFixup = lib.optionalString stdenv.hostPlatform.isElf ''
+    patchelf $out/lib/libvdpau.so --add-rpath $out/lib
+  '';
+
   meta = with lib; {
     homepage = "https://www.freedesktop.org/wiki/Software/VDPAU/";
     description = "Library to use the Video Decode and Presentation API for Unix (VDPAU)";

pkgs/by-name/li/libvdpau/tracing.patch

@@ -0,0 +1,24 @@
+diff --git a/src/vdpau_wrapper.c b/src/vdpau_wrapper.c
+index 79dcb94..6249af4 100644
+--- a/src/vdpau_wrapper.c
++++ b/src/vdpau_wrapper.c
+@@ -185,8 +185,7 @@ static VdpStatus _vdp_open_driver(
+     if (vdpau_trace && atoi(vdpau_trace)) {
+         SetDllHandle * set_dll_handle;
+
+-        _vdp_trace_dll = dlopen(VDPAU_MODULEDIR "/libvdpau_trace.so.1",
+-                                RTLD_NOW | RTLD_GLOBAL);
++        _vdp_trace_dll = dlopen("libvdpau_trace.so.1", RTLD_NOW | RTLD_GLOBAL);
+         if (!_vdp_trace_dll) {
+             fprintf(stderr, "Failed to open VDPAU trace library %s\n", dlerror());
+             _VDP_ERROR_BREAKPOINT();
+diff --git a/trace/meson.build b/trace/meson.build
+index 5381b8b..4af408f 100644
+--- a/trace/meson.build
++++ b/trace/meson.build
+@@ -4,5 +4,4 @@ trace = shared_library('vdpau_trace',
+     dependencies : libdl,
+     version : '1.0.0',
+     install : true,
+-    install_dir : moduledir,
+ )