Add musl to python bootstrapping script (#1758)

Previously, only glibc builds were tracked in the bootstrap script. A
new field `libc` tracks if `gnu` or `musl` are used on linux, while it
is `"none"` everywhere else. I've confirmed that the updated script
works on ubuntu and alpine.

scripts/bootstrap/install.py

@@ -34,6 +34,7 @@ import os
 import platform
 import shutil
 import sys
+import sysconfig
 import tarfile
 import tempfile
 import urllib.parse
@@ -102,7 +103,11 @@ if INSTALL_DIR.exists():
 
 # Install each version
 for version in versions:
-    key = f"{INTERPRETER}-{version}-{PLATFORM_MAP.get(PLATFORM, PLATFORM)}-{ARCH_MAP.get(ARCH, ARCH)}"
+    if platform.system() == "Linux":
+        libc = sysconfig.get_config_var("SOABI").split("-")[-1]
+    else:
+        libc = "none"
+    key = f"{INTERPRETER}-{version}-{PLATFORM_MAP.get(PLATFORM, PLATFORM)}-{ARCH_MAP.get(ARCH, ARCH)}-{libc}"
     install_dir = INSTALL_DIR / f"{INTERPRETER}@{version}"
     print(f"Installing {key}")