configure.ac: add missing \ in avx2 test

Fixes a warning of the form:

```
configure: line 15023: -a: command not found
```

Bug: 525074821
Fixed: 525074821
Change-Id: I46b989afb092fa5b423cfbe16527e71fd75c56e0
1 file changed
tree: d3ffa553b28bc474af915b071a627d6f235f67bf
  1. cmake/
  2. doc/
  3. examples/
  4. extras/
  5. fuzzer/
  6. gradle/
  7. imageio/
  8. infra/
  9. m4/
  10. man/
  11. sharpyuv/
  12. src/
  13. swig/
  14. tests/
  15. webp_js/
  16. .clang-format
  17. .cmake-format.py
  18. .gitattributes
  19. .gitignore
  20. .mailmap
  21. .pylintrc
  22. .style.yapf
  23. Android.mk
  24. AUTHORS
  25. autogen.sh
  26. build.gradle
  27. ChangeLog
  28. CMakeLists.txt
  29. codereview.settings
  30. configure.ac
  31. CONTRIBUTING.md
  32. COPYING
  33. gradle.properties
  34. gradlew
  35. gradlew.bat
  36. iosbuild.sh
  37. Makefile.am
  38. makefile.unix
  39. Makefile.vc
  40. NEWS
  41. PATENTS
  42. PRESUBMIT.py
  43. README.md
  44. xcframeworkbuild.sh
README.md

WebP Codec

      __   __  ____  ____  ____
     /  \\/  \/  _ \/  _ )/  _ \
     \       /   __/  _  \   __/
      \__\__/\____/\_____/__/ ____  ___
            / _/ /    \    \ /  _ \/ _/
           /  \_/   / /   \ \   __/  \__
           \____/____/\_____/_____/____/v1.6.0

WebP codec is a library to encode and decode images in WebP format. This package contains the library that can be used in other programs to add WebP support, as well as the command line tools ‘cwebp’ and ‘dwebp’ to compress and decompress images respectively.

See https://developers.google.com/speed/webp for details on the image format.

The latest source tree is available at https://chromium.googlesource.com/webm/libwebp

It is released under the same license as the WebM project. See https://www.webmproject.org/license/software/ or the “COPYING” file for details. An additional intellectual property rights grant can be found in the file PATENTS.

Building

See the building documentation.

Encoding and Decoding Tools

The examples/ directory contains tools to encode and decode images and animations, view information about WebP images, and more. See the tools documentation.

APIs

See the APIs documentation, and API usage examples in the examples/ directory.

Bugs

Please report all bugs in the WebP component of the issue tracker. For security reports, select ‘Security report’ from the Template dropdown.

Patches welcome! See how to contribute.

Discuss

Email: webp-discuss@webmproject.org

Web: https://groups.google.com/a/webmproject.org/group/webp-discuss