Handle absolute paths in extension_dir containing forward slashes

[bwoebi]

extension_dir = c:/php/ext is also valid on Windows.

Fixes #2786.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 78.64%. Comparing base (d75a84d) to head (d8f7830).

Additional details and impacted files

[](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2798?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog) ```diff @@ Coverage Diff @@ ## master #2798 +/- ## ============================================ + Coverage 76.68% 78.64% +1.95% Complexity 2452 2452 ============================================ Files 169 143 -26 Lines 18052 14276 -3776 Branches 913 0 -913 ============================================ - Hits 13844 11228 -2616 + Misses 3713 3048 -665 + Partials 495 0 -495 ``` | [Flag](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2798/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog) | Coverage Δ | | |---|---|---| | [appsec-extension](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2798/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog) | `?` | | | [tracer-extension](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2798/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog) | `79.21% <ø> (ø)` | | | [tracer-php](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2798/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog) | `78.40% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog#carryforward-flags-in-the-pull-request-comment) to find out more. [see 26 files with indirect coverage changes](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2798/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog) ------ [Continue to review full report in Codecov by Sentry](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2798?dropdown=coverage&src=pr&el=continue&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog). > **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog) > `Δ = absolute (impact)`, `ø = not affected`, `? = missing data` > Powered by [Codecov](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2798?dropdown=coverage&src=pr&el=footer&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog). Last update [d75a84d...d8f7830](https://app.codecov.io/gh/DataDog/dd-trace-php/pull/2798?dropdown=coverage&src=pr&el=lastupdated&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=DataDog).