[FileAccessor] Use ruby-macho to determine whether binaries are dynamic or not

Gemfile.lock

@@ -120,6 +120,7 @@ PATH
       gh_inspector (~> 1.0)
       molinillo (~> 0.5.1, != 0.5.2)
       nap (~> 1.0)
+      ruby-macho (~> 0.2.5)
       xcodeproj (>= 1.3.3, < 2.0)
 
 GEM
@@ -229,6 +230,7 @@ GEM
       ruby-progressbar (~> 1.7)
       unicode-display_width (~> 0.3)
     ruby-graphviz (1.2.2)
+    ruby-macho (0.2.5)
     ruby-prof (0.15.2)
     ruby-progressbar (1.7.5)
     safe_yaml (1.0.4)

cocoapods.gemspec

@@ -47,6 +47,7 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency 'fourflusher',   '~> 2.0.1'
   s.add_runtime_dependency 'gh_inspector',  '~> 1.0'
   s.add_runtime_dependency 'nap',           '~> 1.0'
+  s.add_runtime_dependency 'ruby-macho',    '~> 0.2.5'
 
   s.add_development_dependency 'bacon', '~> 1.1'
   s.add_development_dependency 'bundler', '~> 1.3'

lib/cocoapods/sandbox/file_accessor.rb

+autoload :MachO, 'macho'
+
 module Pod
   class Sandbox
     # Resolves the file patterns of a specification against its root directory,
@@ -371,8 +373,9 @@ module Pod
       #
       def dynamic_binary?(binary)
         return unless binary.file?
-        output, status = Executable.capture_command('file', [binary], :capture => :out)
-        status.success? && output =~ /dynamically linked/
+        MachO.open(binary).dylib?
+      rescue MachO::MachOError
+        false
       end
 
       #-----------------------------------------------------------------------#