diff --git a/Modules/Setup b/Modules/Setup
index 11ddd0c7b2..9b8b5158c4 100644
--- a/Modules/Setup
+++ b/Modules/Setup
@@ -168,7 +168,7 @@ _symtable symtablemodule.c
 
 #array arraymodule.c	# array objects
 #cmath cmathmodule.c _math.c # -lm # complex math library functions
-#math mathmodule.c _math.c # -lm # math library functions, e.g. sin()
+math mathmodule.c _math.c # -lm # math library functions, e.g. sin()
 #_contextvars _contextvarsmodule.c  # Context Variables
 #_struct _struct.c	# binary structure packing/unpacking
 #_weakref _weakref.c	# basic weak reference support
@@ -192,7 +192,7 @@ _symtable symtablemodule.c
 #fcntl fcntlmodule.c	# fcntl(2) and ioctl(2)
 #spwd spwdmodule.c		# spwd(3)
 #grp grpmodule.c		# grp(3)
-#select selectmodule.c	# select(2); not on ancient System V
+select selectmodule.c	# select(2); not on ancient System V
 
 # Memory-mapped files (also works on Win32).
 #mmap mmapmodule.c
@@ -223,7 +223,7 @@ _symtable symtablemodule.c
 #termios termios.c	# Steen Lumholt's termios module
 #resource resource.c	# Jeremy Hylton's rlimit interface
 
-#_posixsubprocess _posixsubprocess.c  # POSIX subprocess module helper
+_posixsubprocess _posixsubprocess.c  # POSIX subprocess module helper
 
 # Multimedia modules -- off by default.
 # These don't work for 64-bit platforms!!!
@@ -239,18 +239,18 @@ _symtable symtablemodule.c
 # The _md5 module implements the RSA Data Security, Inc. MD5
 # Message-Digest Algorithm, described in RFC 1321.
 
-#_md5 md5module.c
+_md5 md5module.c
 
 
 # The _sha module implements the SHA checksum algorithms.
 # (NIST's Secure Hash Algorithms.)
-#_sha1 sha1module.c
-#_sha256 sha256module.c
-#_sha512 sha512module.c
-#_sha3 _sha3/sha3module.c
+_sha1 sha1module.c
+_sha256 sha256module.c
+_sha512 sha512module.c
+_sha3 _sha3/sha3module.c
 
 # _blake module
-#_blake2 _blake2/blake2module.c _blake2/blake2b_impl.c _blake2/blake2s_impl.c
+_blake2 _blake2/blake2module.c _blake2/blake2b_impl.c _blake2/blake2s_impl.c
 
 # The _tkinter module.
 #
diff --git a/setup.py b/setup.py
index b96961073b..e1dbd71bb4 100644
--- a/setup.py
+++ b/setup.py
@@ -134,7 +134,8 @@ def macosx_sdk_root():
     cflags = sysconfig.get_config_var('CFLAGS')
     m = re.search(r'-isysroot\s+(\S+)', cflags)
     if m is None:
-        sysroot = '/'
+        import subprocess
+        sysroot = subprocess.check_output(["xcrun", "--show-sdk-path"]).decode("utf-8").strip('\n')
     else:
         sysroot = m.group(1)
     return sysroot
@@ -146,6 +147,7 @@ def is_macosx_sdk_path(path):
     """
     return ( (path.startswith('/usr/') and not path.startswith('/usr/local'))
                 or path.startswith('/System/')
+                or path.startswith('/Applications/')
                 or path.startswith('/Library/') )