Disable use of missing arm neon function in libpng
Disable use of missing arm neon function in libpng

This was causing pdfium_diff to fail to link on ARM/linux
due to missing neon-specifc symbols.  Ideally we could
add the missing symbols (and update the latest version
of libpng), but that can happen in a separate CL.

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/1581193007 .

andoma/pdfium,DrAlexx/pdfium,andoma/pdfium,andoma/pdfium,DrAlexx/pdfium,andoma/pdfium,DrAlexx/pdfium,DrAlexx/pdfium