Add various self-explanatory changes

* meson: On Linux when compiling with gcc, use zlib.map

Otherwise some symbols are not visible, and as meson sets
rpath to the path of our built libz, things then fail when
for example compiling against a system-wide libpng with:

undefined reference to `gzdirect@ZLIB_1.2.2.3'

* meson: install headers and a pkg-config file
* Add windows resource file
* Add zlib.def for windows dll
* Add MSVC required defines
* Import latest LICENSE.build and readme.txt

LICENSE.build

@@ -0,0 +1,19 @@
+Copyright (c) 2018 The Meson development team
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

meson.build

@@ -1,5 +1,16 @@
 project('zlib', 'c', version : '1.2.11', license : 'zlib')
 
+cc = meson.get_compiler('c')
+
+link_args = []
+if cc.get_id() == 'msvc'
+  add_project_arguments('-D_CRT_SECURE_NO_DEPRECATE',
+    '-D_CRT_NONSTDC_NO_DEPRECATE', language : 'c')
+elif cc.get_id() == 'gcc' and host_machine.system() != 'windows'
+  vflag = '-Wl,--version-script,@0@/zlib.map'.format(meson.current_source_dir())
+  link_args += [vflag]
+endif
+
 src = files([
   'adler32.c',
   'crc32.c',
@@ -17,10 +28,32 @@ src = files([
   'gzread.c',
   'gzwrite.c'])
 
-zlib = library('z', src)
+headers = files(['zconf.h', 'zlib.h'])
+
+if host_machine.system() == 'windows'
+  win = import('windows')
+  win_args = []
+  if cc.get_id() != 'msvc'
+    win_args += '-DGCC_WINDRES'
+  endif
+  src += win.compile_resources('win32/zlib1.rc', args : win_args)
+endif
+
+zlib = library('z', src,
+  link_args : link_args,
+  vs_module_defs : 'win32/zlib.def',
+  install : true)
 
 incdir = include_directories('.')
 
 zlib_dep = declare_dependency(
   link_with : zlib,
   include_directories : incdir)
+
+install_headers(headers)
+
+pkg = import('pkgconfig')
+
+pkg.generate(name: 'zlib',
+             description: 'zlib compression library',
+             libraries: zlib)

readme.txt

@@ -1,2 +1,3 @@
-This is a repository that provides Wrap packaging to Zlib. The exact
-format is not yet clear so this is flying at the seats of pants.
+This repository contains a Meson build definition for project zlib.
+
+For more information please see http://mesonbuild.com.