*/*: Add := to virtual/zlib deps

Add := to virtual/zlib deps, part 1

Done via:

```
git grep -l virtual/zlib$ | xargs sed -i -e 's@virtual/zlib$@&:=@'
```

Add := to virtual/zlib deps

Done via:

```
git grep -l 'virtual/zlib ' |
  xargs sed -i -e 's@virtual/zlib @virtual/zlib:= @g'
```

Unify virtual/zlib:0= to virtual/zlib:=

Done via:

```
git grep -l 'virtual/zlib:0=' |
  xargs sed -i -e 's@virtual/zlib:0=@virtual/zlib:=@g'
```

Add := to virtual/zlib deps, part 3

Done via:

```
git grep -l 'virtual/zlib:0' |
  xargs sed -i -e 's@virtual/zlib:0@virtual/zlib:=@g'
git grep -l 'virtual/zlib:=/' |
  xargs sed -i -e 's@virtual/zlib:=/@virtual/zlib:0/@g'
```

Add := to virtual/zlib deps, part 4

Done via:

```
git grep -l 'virtual/zlib\[' |
  xargs sed -i -e 's@virtual/zlib\[@virtual/zlib:=\[@g'
```

Use := on virtual/zlib deps, part 5

Done via:

```
git grep -l 'virtual/zlib-' |
  xargs sed -i -r -e 's@virtual/zlib-[0-9.]*(-r[0-9]*)?@&:=@g'
git grep -l 'virtual/zlib-' | xargs sed -i -e 's@:=:=@:=@g'
pkgcheck scan --commits \
  -c SourcingCheck,VisibilityCheck,DependencyCheck --exit error
```

Use := on virtual/zlib deps, part 6

Done via:

```
git grep -l 'virtual/zlib"' | xargs sed -i -e 's@virtual/zlib"@virtual/zlib:="@'
```

Signed-off-by: Paul Zander <negril.nx+gentoo@gmail.com>

games-roguelike/cataclysm-dda/cataclysm-dda-0h.ebuild

@@ -37,7 +37,7 @@ REQUIRED_USE="soundpack? ( sound ) sound? ( tiles ) \
 RESTRICT="!test? ( test )"
 
 RDEPEND="
-	virtual/zlib
+	virtual/zlib:=
 	ncurses? ( sys-libs/ncurses )
 	tiles? (
 		media-libs/libsdl2[video]

games-roguelike/cataclysm-dda/cataclysm-dda-9999.ebuild

@@ -36,7 +36,7 @@ REQUIRED_USE="soundpack? ( sound ) sound? ( tiles ) \
 RESTRICT="!test? ( test )"
 
 RDEPEND="
-	virtual/zlib
+	virtual/zlib:=
 	ncurses? ( sys-libs/ncurses )
 	tiles? (
 		media-libs/libsdl2[video]