Fix GCC C++20 modules compilation #5103 (#5164)

* Fix: Add GCC diagnostic pragmas for C++ modules support (issue #5103)

Signed-off-by: hariomphulre <hariiomphullre@gmail.com>

* Fix: GCC C++20 modules with __cplusplus >= 202002L check (#5103)

Signed-off-by: hariomphulre <hariiomphullre@gmail.com>

Signed-off-by: hariomphulre <hariiomphullre@gmail.com>

* Fix: Remove indentation from nested preprocessor directives and disable astyle preprocessor indentation

Signed-off-by: hariomphulre <hariiomphullre@gmail.com>

* Update amalgamated files with correct preprocessor directive indentation

Signed-off-by: hariomphulre <hariiomphullre@gmail.com>

* Fix GCC build for issue #5103; refresh amalgamated header

Signed-off-by: hariomphulre <hariiomphullre@gmail.com>

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Signed-off-by: hariomphulre <hariiomphullre@gmail.com>