Instrumentation partly broken with opcache

Note: If you are using opcache with PHP 7.3 or newer, it is advised to skip this version in favor of 0.76.1.

As part of a major refactor of our instrumenting code, we made ourselves incompatible with JIT (it will report an error that JIT will be disabled, but still work).
Additionally, with opcache active, a lot of user functions are not traceable anymore on PHP 7.3 and newer. This means that the resulting traces will be missing a lot of information.

Tracer

Added

• Add B3 headers injection and extraction #1629
• Collect http.client_ip #1621

Changed

• Filter x-datadog-tags for _dd.p. prefix and add DDTrace\add_distributed_tag #1618
• ​​Rename query string obfuscation variable #1630
• Collect query string by default and obfuscate #1615
• Update regex to account for URL encoding #1622
• Update library versions used in tests + support plesk paths #1632
• Remove service name propagation #1635, #1636
• Add integration loaded output for deferred integrations on DD_TRACE_DEBUG=1 #1639
• ​Reduce memory footprint of strpprintf #1640
• New implementation for hooks #1617
• (PHP 5) Remove service name propagation and filter x-datadog-tags for _dd.p. prefix #1636

Fixed

• Fix crash with numerical value in $_SERVER array #1634
• Fix missing query string on http.url from integrations #1642

Internal changes

• Add link to compatibility requirements in README.md #1610
• Manually build PHP for randomized tests images #1616
• Eliminate PHP 5 references from master #1626
• Remove PHP 5 from CI and fetch it instead from the latest PHP-5 branch build #1624
• Fix test_web on PHP 8.0 #1631
• Add g1a/composer-test-scenarios and symfony/flex to composer allow-plugin list #1637
• (PHP 5) Run Wordpress testsuite actually against PHP 5 #1638
• Test debian bullseye instead of stretch in CI #1644
• Update rel env to use 0.75.0 (#1620)
• Disable clang format check in CI #1619
• Add one more allow-plugins in root composer.json #1646
• (PHP 5) Add g1a/composer-test-scenarios and symfony/flex to composer allow-plugin list #1647

Profiling (v0.7.0)

Changed

• Do not upload empty profiles. See DataDog/dd-prof-php@e03ff23 for details.

Fixed

• Fix a small memory leak with env var handling.

Added

• Add SAPI as profile tag.
• Add support for DD_PROFILING_EXPERIMENTAL_CPU_TIME_ENABLED env var. It previously supported this functionality under a different, undocumented name.