Add PyYAML and libyaml (#1181)

Co-authored-by: daoxian <daoxian@alibaba-inc.com>
Co-authored-by: Roman Yurchak <rth.yurchak@gmail.com>

packages/libyaml/meta.yaml

@@ -0,0 +1,14 @@
+package:
+  name: libyaml
+  version: 0.2.1
+
+source:
+  url: https://github.com/yaml/libyaml/archive/0.2.1.zip
+
+build:
+  library: true
+  script: |
+    CFLAGS="-fPIC" emcmake cmake -DCMAKE_INSTALL_PREFIX=.. .
+    emmake make -j ${PYODIDE_JOBS:-3}
+    ln -s libyaml-0.2.1/libyaml_static.a ../libyaml.a
+    ln -s libyaml-0.2.1/include ..

packages/pyyaml/meta.yaml

@@ -0,0 +1,28 @@
+package:
+  name: pyyaml
+  version: 5.3.1
+
+source:
+  # path: downloads/pyyaml-5.3.1
+  url: https://github.com/yaml/pyyaml/archive/5.3.1.zip
+
+  patches:
+    - patches/Makefile.patch
+    - patches/setup.cfg.patch
+
+build:
+  skip_host: True
+  cflags: |
+    -I../../../../cpython/installs/python-3.8.2/include/python3.8
+    -I../../../../emsdk/emsdk/fastcomp/emscripten/system/include/libc
+    -I../../../libyaml/build/include
+  ldflags: |
+    -L../../../libyaml/build/
+
+requirements:
+  run:
+    - libyaml
+
+test:
+  imports:
+    - yaml

packages/pyyaml/patches/Makefile.patch

@@ -0,0 +1,11 @@
+--- downloads/pyyaml-5.3.1/Makefile	2020-03-18 21:09:19.000000000 +0000
++++ patches/Makefile	2020-11-20 06:33:24.117490628 +0000
+@@ -1,7 +1,7 @@
+ 
+ .PHONY: default build buildext force forceext install installext test testext dist clean
+ 
+-PYTHON=/usr/bin/python
++PYTHON=/bin/env python
+ TEST=
+ PARAMETERS=
+ 

packages/pyyaml/patches/setup.cfg.patch

@@ -0,0 +1,18 @@
+--- downloads/pyyaml-5.3.1/setup.cfg	2021-01-24 16:20:43.372414420 +0000
++++ patches/setup.cfg	2021-01-24 16:20:49.767657201 +0000
+@@ -13,7 +13,7 @@
+ #compiler=mingw32
+ 
+ # Additional preprocessor definitions might be required.
+-#define=YAML_DECLARE_STATIC
++define=YAML_DECLARE_STATIC
+ 
+ # The following options are used to build PyYAML Windows installer
+ # for Python 2.7 on my PC:
+@@ -22,4 +22,4 @@
+ #define=YAML_DECLARE_STATIC
+ 
+ [metadata]
+-license_file = LICENSE
+\ No newline at end of file
++license_file = LICENSE

packages/pyyaml/patches/setup.py.patch

@@ -0,0 +1,11 @@
+--- downloads/pyyaml-5.3.1/setup.py	2020-03-18 21:09:19.000000000 +0000
++++ patches/setup.py	2020-11-24 06:47:26.652992652 +0000
+@@ -287,6 +287,8 @@ if bdist_wheel:
+ 
+ 
+ if __name__ == '__main__':
++    from distutils import sysconfig
++    sysconfig._config_vars['EXT_SUFFIX'] = '.js'
+ 
+     setup(
+         name=NAME,