Fix `strip_symbols.sh` on mac; bump libc to include utime.h (#116)

* strip_symbols.sh: make it work on mac as well

* wasi-libc: added utime, point at master

src/wasi-libc

@@ -1 +1 @@
-Subproject commit 018057e043b82031e44a273790098eb8d3121619
+Subproject commit 7b92f334e69c60a1d1c5d3e289790d790b9a185b

strip_symbols.sh

@@ -1,8 +1,14 @@
-#!/usr/bin/env sh
+#!/usr/bin/env bash
 set -e
 
 DIRECTORY=${1:-/opt/wasi-sdk/bin}
+if [[ "$OSTYPE" == "darwin"* ]]; then
+# macos find doesnt support -executable so we fall back on having a permission
+# bit to execute:
+EXECUTABLES=$(find ${DIRECTORY} -type f -perm +111)
+else
 EXECUTABLES=$(find ${DIRECTORY} -type f -executable)
+fi
 for e in ${EXECUTABLES}; do
   echo "Stripping symbols: ${e}"
   strip ${e} || echo "Failed to strip symbols for ${e}; continuing on."