Merge pull request #371 from libgit2/jspahrsummers-patch-1

Enable libgit2 thread safety for iOS

Author: joshaber

script/update_libgit2_ios

@@ -53,6 +53,7 @@ function build_libgit2 ()
         -DOPENSSL_CRYPTO_LIBRARY:FILEPATH=../../External/ios-openssl/lib/libcrypto.a \
         -DCMAKE_INSTALL_PREFIX:PATH="${INSTALL_PREFIX}/" \
         -DBUILD_CLAR:BOOL=OFF \
+        -DTHREADSAFE:BOOL=ON \
         "${SYS_ROOT}" \
         -DCMAKE_OSX_ARCHITECTURES:STRING="${ARCH}" \
         .. >> "${LOG}" 2>&1