build-system/meson: Remove RUNPATH workarounds.

* guix/build-system/meson.scm (default-patchelf): Remove.
(lower)[build-inputs]: Remove PATCHELF.
(meson-build): Don't delete 'fix-runpath' phase on armhf.
* guix/build/meson-build-system.scm (configure): Add "--c_link_args" and
  "-cpp_link_args" instead of setting LDFLAGS.
(meson-build): Don't apply 'fix-runpath' phase.

guix/build-system/meson.scm

@@ -58,12 +58,6 @@ (define (default-meson)
   (let ((module (resolve-interface '(gnu packages build-tools))))
     (module-ref module 'meson-for-build)))
 
-(define (default-patchelf)
-  "Return the default patchelf package."
-  ;; Lazily resolve the binding to avoid a circular dependency.
-  (let ((module (resolve-interface '(gnu packages elf))))
-    (module-ref module 'patchelf)))
-
 (define* (lower name
                 #:key source inputs native-inputs outputs system target
                 (meson (default-meson))
@@ -81,15 +75,6 @@ (define private-keywords
          (system system)
          (build-inputs `(("meson" ,meson)
                          ("ninja" ,ninja)
-                         ;; XXX PatchELF fails to build on armhf, so we skip
-                         ;; the 'fix-runpath' phase there for now.  It is used
-                         ;; to avoid superfluous entries in RUNPATH as described
-                         ;; in <https://bugs.gnu.org/28444#46>, so armhf may now
-                         ;; have different runtime dependencies from other arches.
-                         ,@(if (not (string-prefix? "arm" (or (%current-target-system)
-                                                              (%current-system))))
-                               `(("patchelf" ,(default-patchelf)))
-                               '())
                          ,@native-inputs))
          (host-inputs `(,@(if source
                               `(("source" ,source))
@@ -147,10 +132,7 @@ (define builder
                     #:inputs %build-inputs
                     #:search-paths ',(map search-path-specification->sexp
                                           search-paths)
-                    #:phases
-                    (if (string-prefix? "arm" ,system)
-                        (modify-phases build-phases (delete 'fix-runpath))
-                        build-phases)
+                    #:phases build-phases
                     #:configure-flags ,configure-flags
                     #:build-type ,build-type
                     #:tests? ,tests?

guix/build/meson-build-system.scm

@@ -1,5 +1,6 @@
 ;;; GNU Guix --- Functional package management for GNU
 ;;; Copyright © 2017 Peter Mikkelsen <petermikkelsen10@gmail.com>
+;;; Copyright © 2018 Marius Bakke <mbakke@fastmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -44,18 +45,13 @@ (define* (configure #:key outputs configure-flags build-type
          (prefix (assoc-ref outputs "out"))
          (args `(,(string-append "--prefix=" prefix)
                  ,(string-append "--buildtype=" build-type)
+                 ,(string-append "-Dc_link_args=-Wl,-rpath="
+                                 (assoc-ref outputs "out") "/lib")
+                 ,(string-append "-Dcpp_link_args=-Wl,-rpath="
+                                 (assoc-ref outputs "out") "/lib")
                  ,@configure-flags
                  ,source-dir)))
 
-    ;; Meson lacks good facilities for dealing with RUNPATH, so we
-    ;; add the output "lib" directory here to avoid doing that in
-    ;; many users.  Related issues:
-    ;; * <https://github.com/mesonbuild/meson/issues/314>
-    ;; * <https://github.com/mesonbuild/meson/issues/3038>
-    ;; * <https://github.com/NixOS/nixpkgs/issues/31222>
-    (unless (getenv "LDFLAGS")
-      (setenv "LDFLAGS" (string-append "-Wl,-rpath=" out "/lib")))
-
     (mkdir build-dir)
     (chdir build-dir)
     (apply invoke "meson" args)))
@@ -148,8 +144,13 @@ (define %standard-phases
     (replace 'configure configure)
     (replace 'build build)
     (replace 'check check)
-    (replace 'install install)
-    (add-after 'strip 'fix-runpath fix-runpath)))
+    ;; XXX: We used to have 'fix-runpath' here, but it appears no longer
+    ;; necessary with newer Meson.  However on 'core-updates' there is a
+    ;; useful 'strip-runpath' procedure to ensure no bogus directories in
+    ;; RUNPATH (remember that we tell Meson to not touch RUNPATH in
+    ;; (@ (gnu packages build-tools) meson-for-build)), so it should be
+    ;; re-added there sans the augment-rpath calls (which are not needed).
+    (replace 'install install)))
 
 (define* (meson-build #:key inputs phases
                       #:allow-other-keys #:rest args)