[andr2k]

pie install php/gd currently fails during package resolution because GD is excluded from the bundled-extension repository. This registers php/gd and builds it with the same image features as the target PHP.

pie install php/gd --force

Behaviour

• Detected features. On Unix builds PIE reads main/php_config.h from php-config --include-dir and adds the matching configure flag for each feature the target PHP was built with:

  php_config.h define	flag added
  HAVE_GD_FREETYPE	--with-freetype
  HAVE_GD_JPG	--with-jpeg
  HAVE_GD_XPM	--with-xpm
  HAVE_GD_WEBP	--with-webp
  HAVE_GD_AVIF	--with-avif

• User-supplied flags. The same five flags are declared as configure options, so they can be passed explicitly, e.g. when the header has no GD defines (the official Docker images). A flag the user passes is never duplicated, and a value form such as --with-jpeg=/opt/jpeg is left as given.

• No header, no change. If php-config or php_config.h is unavailable, nothing is added.

• The development libraries for every enabled feature must be installed, whether the flag was detected or passed.

• The existing build-provider refusal and --force override are unchanged.

• The package requires PHP 7.4+, when these configure flag names were introduced.

Implementation

• BundledPhpExtensionsRepository: registers gd with its configure-options, and adds augmentConfigureOptionsForPhpBundledExtensions(), which applies the mapping above for php/gd only.
• PhpBinaryPath::phpConfigHeader(): returns the contents of php_config.h, or null.
• UnixBuild: calls the augmentation after the libdir detection, before configure.

Tests

• Unit: the declared options; the detection matrix (all features, one feature, #undef, existing options kept first, no duplicate, user value not overridden, no header, other extension untouched); phpConfigHeader() with and without the header file.
• End-to-end (test/end-to-end/Dockerfile): pie install --force php/gd against Alpine's and Homebrew's PHP, each first asserting the header defines HAVE_GD_FREETYPE; the Alpine target also checks the built extension loads with LD_BIND_NOW=1.
• CI: libjpeg-dev is added to the bundled-extension job, where test/install-bundled-php-exts.php now installs php/gd with the rest.

The historical ft2build.h failure recorded in the original GD review thread does not occur in these builds. This PR does not claim to establish its original cause.

Discussion: #781.

PR submitter checklist

• I have read CONTRIBUTING.md
• I discussed this feature with the maintainers in #781
• I have added appropriate tests
• I confirm that I have the right to submit this under the project's open source licence

[asgrim]

Thanks @andr2k - sorry it took a while to get to. I had to work out the original issue with ft2build.h being missing; it was all to do with the flags the target PHP build has; Ondrej repos for example don't have the HAVE_GD_FREETYPE flag; I added some detection to look into php_config.h to figure out the flags, and as a result add the effective --with-... configure options which is why your PR worked originally; just now it has some evidence to support the change 😁