Link zlib statically for windows (#35)

* Add zlib 1.2.11 sources

* link zlib statically for windows

third_party/zlib/contrib/ada/readme.txt

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+                        ZLib for Ada thick binding (ZLib.Ada)
+                        Release 1.3
+
+ZLib.Ada is a thick binding interface to the popular ZLib data
+compression library, available at http://www.gzip.org/zlib/.
+It provides Ada-style access to the ZLib C library.
+
+
+        Here are the main changes since ZLib.Ada 1.2:
+
+- Attension: ZLib.Read generic routine have a initialization requirement
+  for Read_Last parameter now. It is a bit incompartible with previous version,
+  but extends functionality, we could use new parameters Allow_Read_Some and
+  Flush now.
+
+- Added Is_Open routines to ZLib and ZLib.Streams packages.
+
+- Add pragma Assert to check Stream_Element is 8 bit.
+
+- Fix extraction to buffer with exact known decompressed size. Error reported by
+  Steve Sangwine.
+
+- Fix definition of ULong (changed to unsigned_long), fix regression on 64 bits
+  computers. Patch provided by Pascal Obry.
+
+- Add Status_Error exception definition.
+
+- Add pragma Assertion that Ada.Streams.Stream_Element size is 8 bit.
+
+
+        How to build ZLib.Ada under GNAT
+
+You should have the ZLib library already build on your computer, before
+building ZLib.Ada. Make the directory of ZLib.Ada sources current and
+issue the command:
+
+  gnatmake test -largs -L<directory where libz.a is> -lz
+
+Or use the GNAT project file build for GNAT 3.15 or later:
+
+  gnatmake -Pzlib.gpr -L<directory where libz.a is>
+
+
+        How to build ZLib.Ada under Aonix ObjectAda for Win32 7.2.2
+
+1. Make a project with all *.ads and *.adb files from the distribution.
+2. Build the libz.a library from the ZLib C sources.
+3. Rename libz.a to z.lib.
+4. Add the library z.lib to the project.
+5. Add the libc.lib library from the ObjectAda distribution to the project.
+6. Build the executable using test.adb as a main procedure.
+
+
+        How to use ZLib.Ada
+
+The source files test.adb and read.adb are small demo programs that show
+the main functionality of ZLib.Ada.
+
+The routines from the package specifications are commented.
+
+
+Homepage: http://zlib-ada.sourceforge.net/
+Author: Dmitriy Anisimkov <anisimkov@yahoo.com>
+
+Contributors: Pascal Obry <pascal@obry.org>, Steve Sangwine <sjs@essex.ac.uk>