add missing diff option (rust-lang#753)

Author: Stephan Dilly

libgit2-sys/lib.rs

@@ -1172,6 +1172,7 @@ pub const GIT_DIFF_UPDATE_INDEX: git_diff_option_t = 1 << 15;
 pub const GIT_DIFF_INCLUDE_UNREADABLE: git_diff_option_t = 1 << 16;
 pub const GIT_DIFF_INCLUDE_UNREADABLE_AS_UNTRACKED: git_diff_option_t = 1 << 17;
 pub const GIT_DIFF_INDENT_HEURISTIC: git_diff_option_t = 1 << 18;
+pub const GIT_DIFF_IGNORE_BLANK_LINES: git_diff_option_t = 1 << 19;
 pub const GIT_DIFF_FORCE_TEXT: git_diff_option_t = 1 << 20;
 pub const GIT_DIFF_FORCE_BINARY: git_diff_option_t = 1 << 21;
 pub const GIT_DIFF_IGNORE_WHITESPACE: git_diff_option_t = 1 << 22;

src/diff.rs

@@ -814,6 +814,11 @@ impl DiffOptions {
         self.flag(raw::GIT_DIFF_IGNORE_WHITESPACE_EOL, ignore)
     }
 
+    /// Ignore blank lines
+    pub fn ignore_blank_lines(&mut self, ignore: bool) -> &mut DiffOptions {
+        self.flag(raw::GIT_DIFF_IGNORE_BLANK_LINES, ignore)
+    }
+
     /// When generating patch text, include the content of untracked files.
     ///
     /// This automatically turns on `include_untracked` but it does not turn on