ledger: ofx support

Closes Homebrew/homebrew#17354.

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

Formula/ledger.rb

@@ -18,6 +18,7 @@ class Ledger < Formula
   depends_on 'pcre'
   depends_on 'expat'
   depends_on 'cmake' if build.head?
+  depends_on 'libofx' => :optional unless build.head?
 
   def patches
     p = {:p1 => []}
@@ -35,8 +36,14 @@ class Ledger < Formula
       system "./acprep", *args
       system "cmake", "-D", "CMAKE_INSTALL_PREFIX=#{prefix}", "-P", "build/cmake_install.cmake"
     else
+      args = []
+      if build.with? 'libofx'
+        args << "--enable-ofx"
+        # the libofx.h appears to have moved to a subdirectory
+        ENV.append 'CXXFLAGS', "-I#{Formula.factory('libofx').opt_prefix}/include/libofx"
+      end
       system "./configure", "--disable-debug", "--disable-dependency-tracking",
-                            "--prefix=#{prefix}"
+                            "--prefix=#{prefix}", *args
       system 'make'
       ENV.deparallelize
       system 'make install'