gnu: glibc: Improve handling of empty .a files.

This partially reverts 3b2de6529b9d77c8a74d431859a3ec334e9603c2, itself
a followup to 25b30622b4a77cd4b2965b9d62fa310a22413d54.

* gnu/packages/base.scm (glibc)[arguments]: In ‘move-static-libs’ phase,
remove ‘empty-static-libraries’ variable and rewrite
‘empty-static-library?’ to check file type and size.
* gnu/packages/commencement.scm (make-gcc-toolchain): Remove ‘copy-file’
call to create ‘librt.a’.

Change-Id: I33c6825d5b1e6e790dfff494bac1da07d3389e77

2 files changed, 7 insertions, 21 deletions

diff --git a/gnu/packages/base.scm b/gnu/packages/base.scm
index b7e5b0479f..2f48f65caf 100644
--- a/gnu/packages/base.scm
+++ b/gnu/packages/base.scm
@@ -1020,19 +1020,13 @@ the store.")
                      ;; and as such, it is useful to have these ".a" files in
                      ;; OUT in addition to STATIC.
 
-                     ;; XXX: It might be better to determine whether a static
-                     ;; library is empty by some criterion (such as their file
-                     ;; size equaling eight bytes) rather than hardcoding them
-                     ;; by name.
-
-                     ;; XXX: We forgot librt.a for the current version!  In
-                     ;; the meantime, gcc-toolchain provides it, but remove
-                     ;; that fix once librt.a is added here.
-                     (define empty-static-libraries
-                       '("libpthread.a" "libdl.a" "libutil.a" "libanl.a"))
                      (define (empty-static-library? file)
-                       (any (lambda (s)
-                              (string=? file s)) empty-static-libraries))
+                       ;; Return true if FILE is an 'ar' archive with nothing
+                       ;; beyond the header.
+                       (let ((file (string-append (assoc-ref outputs "out")
+                                                  "/lib/" file)))
+                         (and (ar-file? file)
+                              (= (stat:size (stat file)) 8))))
 
                      (define (static-library? file)
                        ;; Return true if FILE is a static library.  The
diff --git a/gnu/packages/commencement.scm b/gnu/packages/commencement.scm
index d6e8da0f32..179b4f2d3e 100644
--- a/gnu/packages/commencement.scm
+++ b/gnu/packages/commencement.scm
@@ -3583,15 +3583,7 @@ COREUTILS-FINAL vs. COREUTILS, etc."
                                                      "libc-debug")))
                        (union-build (assoc-ref %outputs "static")
                                     (list (assoc-ref %build-inputs
-                                                     "libc-static")))
-                       ;; XXX Remove once an empty librt.a is added to
-                       ;; libc:out.
-                       (copy-file
-                        (string-append (assoc-ref %outputs "out")
-                                       "/lib/libpthread.a")
-                        (string-append (assoc-ref %outputs "out")
-                                       "/lib/librt.a"))
-                       #t))))
+                                                     "libc-static")))))))
 
       (native-search-paths
        (append (package-native-search-paths gcc)