[feature][php] large file support for 32bit architectures

[Anwarias]

Hey all,
I have been running into problem with Nextcloud on a 32bit Odroid XU4.
I was unable to upload files larger than 2GB, which apparently is limited by the 32bit PHP version.
Recently i found a post that enables large file support when building PHP.
I tried that myself and compiled php with the following additional flags enable in the PKGBUILD:

$this->bbcode_second_pass_code('', '
build() {
# http://site.icu-project.org/download/61#TOC-Migration-Issues
- CPPFLAGS+=' -DU_USING_ICU_NAMESPACE=1'
+ CPPFLAGS+=' -DU_USING_ICU_NAMESPACE=1 -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64'
')

There is also a performance analysis in the post that shows seemingly no performance impact.

Is there a reason why this is not enabled by default?
How do i go about testing the changes for all architectures without having access to all hardware?
How can i help to the these changes into the official repositories?

Cheers
Anwarias