Fix macOS build. See https://github.com/WebAssembly/binaryen/issues/4299

emsdk.py

diff --git a/emsdk.py b/emsdk.py
index d671d7b..52ce0a1 100644
--- a/emsdk.py
+++ b/emsdk.py
@@ -1071,14 +1071,14 @@
     cmdline = ['cmake'] + generator + ['-DCMAKE_BUILD_TYPE=' + build_type, '-DPYTHON_EXECUTABLE=' + sys.executable]
     # Target macOS 10.11 at minimum, to support widest range of Mac devices from "Mid 2007" and newer:
     # https://en.wikipedia.org/wiki/MacBook_Pro#Supported_macOS_releases
-    cmdline += ['-DCMAKE_OSX_DEPLOYMENT_TARGET=10.11']
+    cmdline += ['-DCMAKE_OSX_DEPLOYMENT_TARGET=10.14']
     cmdline += extra_cmake_args + [src_root]
 
     print('Running CMake: ' + str(cmdline))
 
     # Specify the deployment target also as an env. var, since some Xcode versions
     # read this instead of the CMake field.
-    os.environ['MACOSX_DEPLOYMENT_TARGET'] = '10.11'
+    os.environ['MACOSX_DEPLOYMENT_TARGET'] = '10.14'
 
     def quote_parens(x):
       if ' ' in x: