perl 5.28.0

- work around DYLD_LIBRARY_PATH problem with a symlink
- run `make test` while bottling
- re-enable option to run `make test` on El Capitan and later (was
  already enabled on prior versions), but make it opt-in
- remove unneeded clock_gettime fix for 10.11

Formula/perl.rb

@@ -1,8 +1,8 @@
 class Perl < Formula
   desc "Highly capable, feature-rich programming language"
   homepage "https://www.perl.org/"
-  url "https://www.cpan.org/src/5.0/perl-5.26.2.tar.xz"
-  sha256 "0f8c0fb1b0db4681adb75c3ba0dd77a0472b1b359b9e80efd79fc27b4352132c"
+  url "https://www.cpan.org/src/5.0/perl-5.28.0.tar.xz"
+  sha256 "059b3cb69970d8c8c5964caced0335b4af34ac990c8e61f7e3f90cd1c2d11e49"
   head "https://perl5.git.perl.org/perl.git", :branch => "blead"
 
   bottle do
@@ -12,25 +12,12 @@ class Perl < Formula
   end
 
   option "with-dtrace", "Build with DTrace probes"
-  option "without-test", "Skip running the build test suite"
+  option "with-test", "Run build-time tests"
 
   # Prevent site_perl directories from being removed
   skip_clean "lib/perl5/site_perl"
 
   def install
-    if MacOS.version == :el_capitan && MacOS::Xcode.installed? && MacOS::Xcode.version >= "8.0"
-      %w[cpan/IPC-Cmd/lib/IPC/Cmd.pm dist/Time-HiRes/Changes
-         dist/Time-HiRes/HiRes.pm dist/Time-HiRes/HiRes.xs
-         dist/Time-HiRes/Makefile.PL dist/Time-HiRes/fallback/const-c.inc
-         dist/Time-HiRes/t/clock.t pod/perl588delta.pod
-         pod/perlperf.pod].each do |f|
-        inreplace f do |s|
-          s.gsub! "clock_gettime", "perl_clock_gettime"
-          s.gsub! "clock_getres", "perl_clock_getres", false
-        end
-      end
-    end
-
     args = %W[
       -des
       -Dprefix=#{prefix}
@@ -50,15 +37,20 @@ class Perl < Formula
     args << "-Dusedevel" if build.head?
 
     system "./Configure", *args
-    system "make"
 
-    # OS X El Capitan's SIP feature prevents DYLD_LIBRARY_PATH from being
-    # passed to child processes, which causes the make test step to fail.
+    # macOS's SIP feature prevents DYLD_LIBRARY_PATH from being passed to child
+    # processes, which causes the `make test` step to fail.
     # https://rt.perl.org/Ticket/Display.html?id=126706
     # https://github.com/Homebrew/legacy-homebrew/issues/41716
-    if MacOS.version < :el_capitan
-      system "make", "test" if build.with? "test"
-    end
+    # As of perl 5.28.0 `make` fails, too, so work around it with a symlink.
+    # Reported 25 Jun 2018 https://rt.perl.org/Ticket/Display.html?id=133306
+    (lib/"perl5/#{version}/darwin-thread-multi-2level/CORE").install_symlink buildpath/"libperl.dylib"
+
+    system "make"
+    system "make", "test" if build.with?("test") || build.bottle?
+
+    # Remove the symlink so the library actually gets installed.
+    rm lib/"perl5/#{version}/darwin-thread-multi-2level/CORE/libperl.dylib"
 
     system "make", "install"
   end