Merge pull request #38168 from dtzWill/fix/epoxy-libgl-path

epoxy: explicitly search libGL path as fallback

pkgs/development/libraries/epoxy/default.nix

@@ -25,10 +25,9 @@ stdenv.mkDerivation rec {
     substituteInPlace src/dispatch_common.h --replace "PLATFORM_HAS_GLX 0" "PLATFORM_HAS_GLX 1"
   '';
 
-  # add libGL to rpath because libepoxy dlopen()s libEGL
+  patches = [ ./libgl-path.patch ];
-  postFixup = optionalString stdenv.isLinux ''
+
-    patchelf --set-rpath "${stdenv.lib.makeLibraryPath [ libGL ]}:$(patchelf --print-rpath $out/lib/libepoxy.so.0.0.0)" $out/lib/libepoxy.so.0.0.0
+  NIX_CFLAGS_COMPILE = ''-DLIBGL_PATH="${getLib libGL}/lib"'';
-  '';
 
   meta = {
     description = "A library for handling OpenGL function pointer management";

pkgs/development/libraries/epoxy/libgl-path.patch

@@ -0,0 +1,35 @@
+From 4046e0ac8ed93354c01de5f3b5cae790cce70404 Mon Sep 17 00:00:00 2001
+From: Will Dietz <w@wdtz.org>
+Date: Thu, 29 Mar 2018 07:21:02 -0500
+Subject: [PATCH] Explicitly search LIBGL_PATH as fallback, if defined.
+
+---
+ src/dispatch_common.c | 12 ++++++++++++
+ 1 file changed, 12 insertions(+)
+
+diff --git a/src/dispatch_common.c b/src/dispatch_common.c
+index bc2fb94..776237b 100644
+--- a/src/dispatch_common.c
++++ b/src/dispatch_common.c
+@@ -306,6 +306,18 @@ get_dlopen_handle(void **handle, const char *lib_name, bool exit_on_fail)
+     pthread_mutex_lock(&api.mutex);
+     if (!*handle) {
+         *handle = dlopen(lib_name, RTLD_LAZY | RTLD_LOCAL);
++#ifdef LIBGL_PATH
++        if (!*handle) {
++          char pathbuf[sizeof(LIBGL_PATH) + 1 + 1024 + 1];
++          int l = snprintf(pathbuf, sizeof(pathbuf), "%s/%s", LIBGL_PATH, lib_name);
++          if (l < 0 || l >= sizeof(pathbuf)) {
++            // This really shouldn't happen
++            fprintf(stderr, "Error prefixing library pathname\n");
++            exit(1);
++          }
++          *handle = dlopen(pathbuf, RTLD_LAZY | RTLD_LOCAL);
++        }
++#endif
+         if (!*handle) {
+             if (exit_on_fail) {
+                 fprintf(stderr, "Couldn't open %s: %s\n", lib_name, dlerror());
+-- 
+2.16.3
+