Fix GCC 11 array-bounds warning in P_SetupStateAnimation

See merge request !1614

Fix Debian (.deb) build from making (Project_root)/bin/Linux

See merge request !1595

MSYS2: Don't compile with dynamic base

See merge request !1652

	modified:   src/CMakeLists.txt
	modified:   src/Makefile
	modified:   src/Makefile.d/detect.mk
	modified:   src/r_picformats.h
	modified:   src/sdl/mixer_sound.c

Resolves #671

Fix gme support being effectively disabled

See merge request !1586

Makefile: Improve gcc detection

See merge request !1608

Removing inline here silences the warning somehow, it
could be a GCC bug?

Wasn't working for me until I fixed it.
Turns out gcc really doesn't like giving its name out.
Most of the time it reads argv[0].

Previously took only the filename, so the directory
component was stripped. This broke dependencies for
basically every file.

I found this easier than trying to adjust the makefile, as it uses the same thing to automatically generate the various NO* compile options.

Take advantage of new Makefile in appveyor.yml

See merge request STJr/SRB2!1561

Also changed -Wno-error=implicit-fallthrough to
-Wno-implicit-fallthrough. For some reason Appveyor's
version of GCC is triggering these warnings despite the
comments, so just shut it up.

According to this answer--
https://stackoverflow.com/a/45952425
--Make will always prefer a unix shell, even on Windows,
if one can be found in Path. So we can't check PATH to
determine if it's a Windows shell... this is just too much
bother.

Some issues with the Makefile

See merge request !1553

If a variable is defined as in 'make CC=gcc-10', then that
definition overrides anything other definition in the
Makefile.

After a checkout from before revision, old directories
such as bin/Linux64 only remain if untracked files exist
within. This may be confusing to the user. They may even
use an outdated executable if it is one of those untracked
files.

This is for MSYS2, which requires unix shell commands.

File function is not supported < Make 4.2.

With added textual contrast.

NOOBJDUMP=1 and NOUPX=1 have been removed. Make 'dump'
target to disassemble. UPX=upx to compress executable.

Setting UPX used to cause it to fail. That has been fixed.

Fix console text bleeding

See merge request !1434

Add badge to readme showing latest stable release

See merge request !1510

Fix some compiler warnings

See merge request !1504