This reverts commit 641135ba.

Some badly formatted code has managed to pass through our CI...

(cherry picked from commit 21e53c42)

Also fix documented OpenSSL version, it was updated to 1.0.2l in
67305d1b.

(cherry picked from commit 560fc0f1)

Fixes security vulnerability in our 1.6.31rc01 snapshot.

(cherry picked from commit ee1d0179)

(cherry picked from commit 4950ef74)

(cherry picked from commit 3c5ce736)

(cherry picked from commit bd257153)

When building a profile build it is easy to accidentally create gmon.out
files all over the place. Ignore these so they won't get accidentally
pushed.

(cherry picked from commit aa91640c)

Since we have explicit .gitignore rules for QT creator and several other
editor-specific swap/utility files I'd like to add Eclipse CDT projects
also as this is my editor of choice.

(cherry picked from commit 90ab7162)

(cherry picked from commit d7f08ead)

The functionality was already there but hidden behind a bogus return statement.
Fixes #10485

(cherry picked from commit 5d25f639)

The 'pos' variable passed to get_color() and get_offset() can be
negative if the color ramp itself is empty. This causes a lookup in an
empty position in the color Vector which leads to a crash.

We add a check so we never do a lookup in the color Vector if the
gradient is empty.

This fixes #10501

(cherry picked from commit 67b9d6ee)

(cherry picked from commit 533014b8)

(cherry picked from commit f6ee4cac)

(cherry picked from commit a0457341)

It is no longer the default value ;)

(cherry picked from commit 686294e4)

Fixes #10131

(cherry picked from commit a80371ce)

Fixes #10539 in a diplomatic way (as opposed to telling Gentoo users
to just change their distro or rebuild zlib from upstream...).

(cherry picked from commit 67e6c1b7)

I have not assessed whether they are still all relevant.

(cherry picked from commit 53fffa12)

Godot-specific changes are undone in this commit, they will be readded
and properly documented in the following commit.

(cherry picked from commit 5681b7b6)

off-by-one error in the line count calculation.

Fixes #10411

(cherry picked from commit 58b2f441)

Upstream bug report: https://sourceforge.net/p/mingw-w64/bugs/460/

(cherry picked from commit 2ed87f33)

Fixes #10403

(cherry picked from commit 3f2d806b)

(cherry picked from commit cf2fdcb6)

(cherry picked from commit 78e72c8e)

(cherry picked from commit deaf095d)

This is due to a Godot bug which is now fixed in the master branch, but would require
too much work for a short-lived branch such as 2.1. Building release binaries with GCC 6+
will trigger segfaults due to UB when dereferencing pointers with Object::cast_to.

In theory this check should also be made for Windows cross-compilation with MinGW,
but I am more concerned about Linux distros shipping broken binaries than adventurous
cross-compilers hitting a wall.

See #10683 for a potential better fix, but this close to the 2.1.4 release
I am taking the safe route.

Fix #10642

more efficient atlas packing algorithm

- Change get_rect_region to return UV region instead of pixel rect
- Fixed atlas texture Sprite3D Y offsets being applied in the wrong direction and fixed Flip not adjusting the geometry.
- Changed get_rect_region name to get_rect_region_uv_rect