bbcp: fix implicit int build error with patch

This commit fixes a build failure caused by `main`'s use of an implicit
`int` return type specifier.

The embedded patch just makes the return type explicit.

ISSUE

As of C99, a declaration that lacks a type specifier isn't implicitly
assumed to be int, which causes the build to fail with this error:

    bbcp.C:61:1: error: C++ requires a type specifier for all declarations
    main(int argc, char *argv[], char *envp[])
    ^~~~

ENVIRONMENT

- g++ : Apple LLVM version 5.0 (clang-500.2.76) (based on LLVM 3.3svn)
- OS  : Mac OS X 10.8.5 (Build 12F37)

NOTES

- Confirmed Formula passes audit.
- Also sent the patch to the upstream developer.

Closes Homebrew/homebrew#22832.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Formula/bbcp.rb

@@ -5,6 +5,10 @@ class Bbcp < Formula
   url 'http://www.slac.stanford.edu/~abh/bbcp/bbcp.tgz'
   version '13.05.03.00.0'
   sha1 '218911904b46f7aff3784705581737f53eccbc53'
+  head 'http://www.slac.stanford.edu/~abh/bbcp/bbcp.git'
+
+  # Adds missing required return type specification on 'main'
+  def patches; DATA; end
 
   def install
     mkdir "bin"
@@ -21,3 +25,18 @@ class Bbcp < Formula
     system "#{bin}/bbcp", "--help"
   end
 end
+
+__END__
+diff --git c/src/bbcp.C w/src/bbcp.C
+index 03c6d4e..7116fff 100644
+--- c/src/bbcp.C
++++ w/src/bbcp.C
+@@ -58,7 +58,7 @@ extern bbcp_System   bbcp_OS;
+ /*                                  m a i n                                   */
+ /******************************************************************************/
+   
+-main(int argc, char *argv[], char *envp[])
++int main(int argc, char *argv[], char *envp[])
+ {
+    bbcp_Node     *Source, *Sink;
+    bbcp_Protocol  Protocol;