[wasmtime-py] Build wheels for python37 on linux (#310)

ci/azure-build-wheels.yml

@@ -41,10 +41,24 @@ steps:
     versionSpec: '3.7'
     addToPath: true
   condition: and(succeeded(), ne(variables['Agent.OS'], 'Linux'))
+- bash: sudo bash ci/setup_centos6_python37.sh
+  condition: and(succeeded(), eq(variables['Agent.OS'], 'Linux'))
+
+- bash: sudo pip3 install setuptools wheel==0.31.1 setuptools-rust auditwheel
+  displayName: Install Python dependencies (Linux)
+  condition: and(succeeded(), eq(variables['Agent.OS'], 'Linux'))
+- bash: pip3 install setuptools wheel==0.31.1 setuptools-rust
+  displayName: Install Python dependencies (not Linux)
+  condition: and(succeeded(), ne(variables['Agent.OS'], 'Linux'))
+
 - bash: |
     set -e
-    pip3 install setuptools wheel==0.31.1 setuptools-rust
-    python setup.py bdist_wheel
+    export PYTHON_SYS_EXECUTABLE=`which python3.7`
+    $PYTHON_SYS_EXECUTABLE setup.py bdist_wheel
+  workingDirectory: misc/wasmtime-py
+  displayName: Build wheels py37
+  condition: and(succeeded(), eq(variables['Agent.OS'], 'Linux'))
+- bash: python setup.py bdist_wheel
   workingDirectory: misc/wasmtime-py
   displayName: Build wheels py37
   condition: and(succeeded(), ne(variables['Agent.OS'], 'Linux'))

ci/setup_centos6_python37.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+set -e
+
+# Python 3.6 stands in our way -- nuking it
+yum erase -y rh-python36
+rm -rf /opt/rh/rh-python36
+
+yum install -y gcc bzip2-devel libffi-devel zlib-devel
+
+cd /usr/src/
+
+# pip3.7 needs new openssl
+curl -O -L https://github.com/openssl/openssl/archive/OpenSSL_1_1_1c.tar.gz
+tar -zxvf OpenSSL_1_1_1c.tar.gz
+cd openssl-OpenSSL_1_1_1c
+./Configure shared zlib linux-x86_64
+make -sj4
+make install
+cd ..
+rm -rf openssl-OpenSSL_1_1_1c
+
+# Fixing libssl.so.1.1: cannot open shared object file
+echo "/usr/local/lib64" >> /etc/ld.so.conf && ldconfig
+
+curl -O -L https://www.python.org/ftp/python/3.7.3/Python-3.7.3.tgz
+tar xzf Python-3.7.3.tgz
+cd Python-3.7.3
+./configure
+make -sj4
+make install
+cd ..
+rm -rf Python-3.7.3