firestore_snappy.patch.txt: fix linux gcc inlining build error

[dconeybe]

This is a follow-up to #885 and fixes the Snappy build on some older compilers (e.g. gcc-9.4.0 on linux).

This PR is based on this patch: google/snappy#128

The build error looks like this:

snappy.cc:1017:8: warning: always_inline function might not be inlinable [-Wattributes]
 1017 | size_t AdvanceToNextTag(const uint8_t** ip_p, size_t* tag) {
      |        ^~~~~~~~~~~~~~~~
snappy.cc: In function ‘std::pair<const unsigned char*, long int> snappy::DecompressBranchless(const uint8_t*, const uint8_t*, ptrdiff_t, T, ptrdiff_t) [with T = char*]’:
snappy.cc:1017:8: error: inlining failed in call to always_inline ‘size_t snappy::AdvanceToNextTag(const uint8_t**, size_t*)’: function body can be overwritten at link time
snappy.cc:1097:43: note: called from here
 1097 |         size_t tag_type = AdvanceToNextTag(&ip, &tag);
      |                           ~~~~~~~~~~~~~~~~^~~~~~~~~~~

The fix is to explicitly mark AdvanceToNextTag() as inline.

e.g. https://github.com/firebase/firebase-unity-sdk/runs/5998971917

[github-actions]

❌  Integration test FAILED

Requested by @dconeybe on commit fd054fa
Last updated: Wed Apr 13 11:21 PDT 2022
View integration test log & download artifacts

Failures	Configs
database	[TEST] [FLAKINESS] [Android] [1/3 os: macos] [android_target] (1 failed tests)   FirebaseDatabaseTest.TestInfoConnected
firestore	[TEST] [FAILURE] [iOS] [macos] [1/2 ios_device: simulator_target] (1 failed tests)   NumericTransformsTest.CreateDocumentWithIncrement

Add flaky tests to go/fpl-cpp-flake-tracker

🍞 Dismissed stale approval on external PR.