checking for libwebp... no
configure: error: Package requirements (libwebp) were not met:
No package 'libwebp' found
Consider adjusting the PKG_CONFIG_PATH environment variable if you
installed software in a non-standard prefix.
Alternatively, you may set the environment variables WEBP_CFLAGS
and WEBP_LIBS to avoid the need to call pkg-config.
See the pkg-config man page for more details.