Fix build of python's zlib module

Because python has a hardcoded zlib version which does not match android's ndk r19, and that prevents the build of zlib's module

Note: it seems that we have to point to the right lib and headers, otherwise we wan't succeed in building python's zlib module

Author: opacam

pythonforandroid/python.py

@@ -183,6 +183,33 @@ def add_flags(include_flags, link_dirs, link_libs):
             recipe = Recipe.get_recipe('openssl', self.ctx)
             add_flags(recipe.include_flags(arch),
                       recipe.link_dirs_flags(arch), recipe.link_libs_flags())
+
+        # python build system contains hardcoded zlib version which prevents
+        # the build of zlib module, here we search for android's zlib version
+        # and sets the right flags, so python can be build with android's zlib
+        info("Activating flags for android's zlib")
+        zlib_lib_path = join(self.ctx.ndk_platform, 'usr', 'lib')
+        zlib_includes = join(self.ctx.ndk_dir, 'sysroot', 'usr', 'include')
+        zlib_h = join(zlib_includes, 'zlib.h')
+        try:
+            with open(zlib_h) as fileh:
+                zlib_data = fileh.read()
+        except IOError:
+            raise BuildInterruptingException(
+                "Could not determine android's zlib version, no zlib.h in "
+                "the NDK dir includes"
+            )
+        for line in zlib_data.split('\n'):
+            if line.startswith('#define ZLIB_VERSION '):
+                break
+        else:
+            raise BuildInterruptingException(
+                'Could not parse zlib.h...so we cannot find zlib version,'
+                'required by python build,'
+            )
+        env['ZLIB_VERSION'] = line.replace('#define ZLIB_VERSION ', '')
+        add_flags(' -I' + zlib_includes, ' -L' + zlib_lib_path, ' -lz')
+
         return env
 
     def prebuild_arch(self, arch):

pythonforandroid/recipes/python2/__init__.py

@@ -31,7 +31,8 @@ class Python2Recipe(GuestPythonRecipe):
                'patches/fix-filesystem-default-encoding.patch',
                'patches/fix-gethostbyaddr.patch',
                'patches/fix-posix-declarations.patch',
-               'patches/fix-pwd-gecos.patch']
+               'patches/fix-pwd-gecos.patch',
+               'patches/fix-zlib-version.patch']
 
     configure_args = ('--host={android_host}',
                       '--build={android_build}',

pythonforandroid/recipes/python2/patches/fix-missing-extensions.patch

@@ -1,15 +1,3 @@
-diff -Naurp Python-2.7.15/Modules/Setup.dist.orig Python-2.7.15/Modules/Setup.dist
---- Python-2.7.15/Modules/Setup.dist.orig	2018-04-30 00:47:33.000000000 +0200
-+++ Python-2.7.15/Modules/Setup.dist	2018-11-17 20:40:20.153518694 +0100
-@@ -464,7 +464,7 @@
- # Andrew Kuchling's zlib module.
- # This require zlib 1.1.3 (or later).
- # See http://www.gzip.org/zlib/
--#zlib zlibmodule.c -I$(prefix)/include -L$(exec_prefix)/lib -lz
-+zlib zlibmodule.c -I$(prefix)/include -L$(exec_prefix)/lib -lz
-
- # Interface to the Expat XML parser
- #
 diff -Naurp Python-2.7.15.orig/Makefile.pre.in Python-2.7.15/Makefile.pre.in
 --- Python-2.7.15.orig/Makefile.pre.in	2018-04-30 00:47:33.000000000 +0200
 +++ Python-2.7.15/Makefile.pre.in	2018-11-18 00:43:58.777379280 +0100

pythonforandroid/recipes/python2/patches/fix-zlib-version.patch

@@ -0,0 +1,12 @@
+--- Python-3.7.1/setup.py.orig	2018-10-20 08:04:19.000000000 +0200
++++ Python-3.7.1/setup.py	2019-02-17 00:24:30.715904412 +0100
+@@ -1416,7 +1416,8 @@ class PyBuildExt(build_ext):
+         if zlib_inc is not None:
+             zlib_h = zlib_inc[0] + '/zlib.h'
+             version = '"0.0.0"'
+-            version_req = '"1.1.3"'
++            version_req = '"{}"'.format(
++                os.environ.get('ZLIB_VERSION', '1.1.3'))
+             if host_platform == 'darwin' and is_macosx_sdk_path(zlib_h):
+                 zlib_h = os.path.join(macosx_sdk_root(), zlib_h[1:])
+             with open(zlib_h) as fp:

pythonforandroid/recipes/python3/__init__.py

@@ -22,7 +22,8 @@ class Python3Recipe(GuestPythonRecipe):
     url = 'https://www.python.org/ftp/python/{version}/Python-{version}.tgz'
     name = 'python3'
 
-    patches = ["patches/fix-ctypes-util-find-library.patch"]
+    patches = ['patches/fix-ctypes-util-find-library.patch',
+               'patches/fix-zlib-version.patch']
 
     if sh.which('lld') is not None:
         patches = patches + ["patches/remove-fix-cortex-a8.patch"]

pythonforandroid/recipes/python3/patches/fix-zlib-version.patch

@@ -0,0 +1,12 @@
+--- Python-3.7.1/setup.py.orig	2018-10-20 08:04:19.000000000 +0200
++++ Python-3.7.1/setup.py	2019-02-17 00:24:30.715904412 +0100
+@@ -1410,7 +1410,8 @@ class PyBuildExt(build_ext):
+         if zlib_inc is not None:
+             zlib_h = zlib_inc[0] + '/zlib.h'
+             version = '"0.0.0"'
+-            version_req = '"1.1.3"'
++            version_req = '"{}"'.format(
++                os.environ.get('ZLIB_VERSION', '1.1.3'))
+             if host_platform == 'darwin' and is_macosx_sdk_path(zlib_h):
+                 zlib_h = os.path.join(macosx_sdk_root(), zlib_h[1:])
+             with open(zlib_h) as fp: