fix build with bundled libgd

Move png and jpeg version functions to gd.c so the external library build doesn't include anything from libgd/.

Required GD >= 2.1.0 or GD bundled, this allows us to remove most of the #ifdef

* Remove overflow2, getmbi and skipheaders from gd_compat.h * Add missing return in _php_ctx_getmbi * Reintroduce imagecreatefromxbm by checking for gdCreateImageFromXbm

Allow to use new GD-2.1.0 function from system library

fix #64725, wrong res check

- #64710, check return val

#64710, kill unused vars

#64710, kill unused vars

#64710, kill unused vars

#64710, Implicit declaration

allow use of gdImageCreateFromJpegEx with system libgd

We need both gdImageCreateFromJpeg* and gdImageCreateFromJpeg*Ex

The new (Ex) functions are used with the new ignore_warning parameter

The standard functions are used in _php_image_

We need both gdImageCreateFromJpeg* and gdImageCreateFromJpeg*Ex

The new (Ex) functions are used with the new ignore_warning parameter

The standard functions are used in _php_image_create_from_string,
sent as a function pointer, and call without this optional parameter.

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gd: fix proto comment

gd: provide imageflip with system libgd when available

fix copy/paste in error message

(re)allow WBMP detection with system libgd
provide getbmi and skipheader not exported functions in gd_compat.

temporary disable WBM detection with system libgd, as gdGetC, getmbi and skipheader not exported

lucky that the name is not used, fix name of encoder

add external 2.1 detection and fix gd_compat for 2.1+

fix BELL constant declaration

add WebP support in phpinfo

FALSE on error

fix regression, take #2 (merge issue due to git 1.8 default setting changes)

- add imageaffinematrixget and imagematrixconcat