abook --devel 0.6.0-pre2

Closes Homebrew/homebrew#27338.

Formula/abook.rb

@@ -5,8 +5,20 @@ class Abook < Formula
   url 'https://downloads.sourceforge.net/abook/abook-0.5.6.tar.gz'
   sha1 '79f04f2264c8bd81bbc952b6560c86d69b21615d'
 
+  devel do
+    url 'https://abook.sourceforge.net/devel/abook-0.6.0pre2.tar.gz'
+    sha1 '42a939fba43e51aa011fa185113c12ec4bc1e1ec'
+  end
+
   depends_on 'readline'
 
+  def patches
+    if build.devel?
+      # Remove `inline` from function implementation for clang compatibility
+      DATA
+    end
+  end
+
   def install
     system "./configure", "--disable-debug", "--disable-dependency-tracking",
                           "--prefix=#{prefix}",
@@ -14,3 +26,18 @@ class Abook < Formula
     system "make install"
   end
 end
+
+__END__
+diff --git a/database.c b/database.c
+index 7c47ab6..53bdb9f 100644
+--- a/database.c
++++ b/database.c
+@@ -762,7 +762,7 @@ item_duplicate(list_item dest, list_item src)
+  */
+ 
+ /* quick lookup by "standard" field number */
+-inline int
++int
+ field_id(int i)
+ {
+ 	assert((i >= 0) && (i < ITEM_FIELDS));