Add ld_default package

Add ldd default option

Display the current default, if available

Handle null values elegantly

Remove ldd option since ldd: unrecognized option '-L'

Redesign to not symlink

Add postinstall message

Add logic to find the default ld on initial install

Create ld script in /tmp and clean up afterwards

Add -R runtime option

Clean up paths and add extra error checks

Create ld_default bash shell script

Change to use descriptive switch options

packages/ld_default.rb

+require 'package'
+
+class Ld_default < Package
+  description 'Select the default ld executable and check for libraries in #{CREW_LIB_PREFIX} first'
+  homepage 'https://github.com/skycocker/chromebrew'
+  version '1.0'
+  source_url 'https://raw.githubusercontent.com/skycocker/chromebrew/93aa4dc4d9198e28d84dcf9d59b3ab6b6a94d92c/README.md'
+  source_sha256 '3ec9c6f7ba6a138d07dfb4a372d562cd3ad558b58b6bd447c2dbb52e16b697a5'
+
+  depends_on 'llvm'
+
+  def self.build
+system "cat << 'EOF' > ld_default
+#!/bin/bash
+cd #{CREW_PREFIX}/bin
+type=\$(file ld | cut -d' ' -f2 | tr -d '\\n')
+if [ \"\$type\" == \"ELF\" ]; then
+  current=\$(find . -inum $(ls -i ld 2> /dev/null | cut -d' ' -f1) 2> /dev/null | fgrep 'ld.' 2> /dev/null | cut -d/ -f2 2> /dev/null)
+else
+  slashes=\$(tr -dc '/' <<<'#{CREW_PREFIX}/bin/ld/' | wc -c)
+  current=\$(tail -1 ld | cut -d'/' -f\${slashes} 2> /dev/null | cut -d' ' -f1 2> /dev/null)
+fi
+echo
+echo \"Current default: \$current\"
+echo
+echo 'Enter the ld default:'
+echo 'b = ld.bfd'
+echo 'g = ld.gold'
+echo 'l = ld.lld'
+echo '0 = Cancel'
+while true; do
+  read default
+  case $default in
+    b)
+      current='ld.bfd'
+      break;;
+    g)
+      current='ld.gold'
+      break;;
+    l)
+      current='ld.lld'
+      break;;
+    0)
+      exit;;
+    *)
+      echo 'Please select from one of the options or enter 0 to cancel.'
+  esac
+done
+echo '#!/bin/bash' > /tmp/ld
+echo '#{CREW_PREFIX}/bin/'$current' --library-path #{CREW_LIB_PREFIX} -rpath #{CREW_LIB_PREFIX} \"\$@\"' >> /tmp/ld
+install -Dm755 /tmp/ld #{CREW_PREFIX}/bin/ld
+rm -f /tmp/ld
+EOF"
+  end
+
+  def self.install
+    system "install -Dm755 ld_default #{CREW_DEST_PREFIX}/bin/ld_default"
+  end
+
+  def self.postinstall
+    puts
+    puts "To change the default linker, execute `ld_default`.".lightblue
+    puts
+  end
+end