6 files changed, 21 insertions, 7 deletions
diff --git a/Library/Homebrew/cmd/postinstall.rb b/Library/Homebrew/cmd/postinstall.rb
index e8855b09e..8808a2602 100644
--- a/Library/Homebrew/cmd/postinstall.rb
+++ b/Library/Homebrew/cmd/postinstall.rb
@@ -37,8 +37,10 @@ module Homebrew
         sandbox.allow_write_log(formula)
         sandbox.allow_write_xcode
         sandbox.deny_write_homebrew_repository
-        sandbox.allow_write_path HOMEBREW_PREFIX
         sandbox.allow_write_cellar(formula)
+        Keg::TOP_LEVEL_DIRECTORIES.each do |dir|
+          sandbox.allow_write_path "#{HOMEBREW_PREFIX}/#{dir}"
+        end
         sandbox.exec(*args)
       else
         exec(*args)
diff --git a/Library/Homebrew/dev-cmd/audit.rb b/Library/Homebrew/dev-cmd/audit.rb
index 0112c524f..540925947 100644
--- a/Library/Homebrew/dev-cmd/audit.rb
+++ b/Library/Homebrew/dev-cmd/audit.rb
@@ -1004,6 +1004,13 @@ class FormulaAuditor
       problem "'fails_with :llvm' is now a no-op so should be removed"
     end
 
+    if formula.tap.to_s == "homebrew/core"
+      ["OS.mac?", "OS.linux?"].each do |check|
+        next unless line.include?(check)
+        problem "Don't use #{check}; Homebrew/core only supports macOS"
+      end
+    end
+
     return unless @strict
 
     if line =~ /system ((["'])[^"' ]*(?:\s[^"' ]*)+\2)/
diff --git a/Library/Homebrew/dev-cmd/create.rb b/Library/Homebrew/dev-cmd/create.rb
index 11544dbef..f684f95f6 100644
--- a/Library/Homebrew/dev-cmd/create.rb
+++ b/Library/Homebrew/dev-cmd/create.rb
@@ -119,7 +119,7 @@ class FormulaCreator
     if @version
       @version = Version.create(@version)
     else
-      @version = Pathname.new(url).version
+      @version = Version.detect(url, {})
     end
   end
 
diff --git a/Library/Homebrew/extend/os/mac/diagnostic.rb b/Library/Homebrew/extend/os/mac/diagnostic.rb
index 157e7982b..55be7b191 100644
--- a/Library/Homebrew/extend/os/mac/diagnostic.rb
+++ b/Library/Homebrew/extend/os/mac/diagnostic.rb
@@ -116,7 +116,7 @@ module Homebrew
 
       def check_xcode_minimum_version
         return unless MacOS::Xcode.installed?
-        return unless MacOS::Xcode.minimum_version?
+        return unless MacOS::Xcode.below_minimum_version?
 
         <<-EOS.undent
           Your Xcode (#{MacOS::Xcode.version}) is too outdated.
@@ -127,7 +127,7 @@ module Homebrew
 
       def check_clt_minimum_version
         return unless MacOS::CLT.installed?
-        return unless MacOS::CLT.minimum_version?
+        return unless MacOS::CLT.below_minimum_version?
 
         <<-EOS.undent
           Your Command Line Tools are too outdated.
diff --git a/Library/Homebrew/os/mac/xcode.rb b/Library/Homebrew/os/mac/xcode.rb
index bc1d66ef8..4ab863a5d 100644
--- a/Library/Homebrew/os/mac/xcode.rb
+++ b/Library/Homebrew/os/mac/xcode.rb
@@ -32,7 +32,7 @@ module OS
         end
       end
 
-      def minimum_version?
+      def below_minimum_version?
         version < minimum_version
       end
 
@@ -231,11 +231,16 @@ module OS
         end
       end
 
-      def minimum_version?
+      def below_minimum_version?
+        # Lion was the first version of OS X to ship with a CLT
+        return false if MacOS.version < :lion
         version < minimum_version
       end
 
       def outdated?
+        # Lion was the first version of OS X to ship with a CLT
+        return false if MacOS.version < :lion
+
         if MacOS.version >= :mavericks
           version = Utils.popen_read("#{MAVERICKS_PKG_PATH}/usr/bin/clang --version")
         else
diff --git a/Library/Homebrew/shims/super/cc b/Library/Homebrew/shims/super/cc
index 9d2ee0d34..b0ea705e8 100755
--- a/Library/Homebrew/shims/super/cc
+++ b/Library/Homebrew/shims/super/cc
@@ -31,7 +31,7 @@ class Cmd
     @deps = Set.new(ENV.fetch("HOMEBREW_DEPENDENCIES") { "" }.split(","))
     @formula_prefix = ENV["HOMEBREW_FORMULA_PREFIX"]
     # matches opt or cellar prefix and formula name
-    @keg_regex = %r[(#{Regexp.escape(opt)}|#{Regexp.escape(cellar)})/([\w\-_\+]+)]
+    @keg_regex = %r[(#{Regexp.escape(opt)}|#{Regexp.escape(cellar)})/([\w+-.@]+)]
   end
 
   def mode