Build with -Wl,-z,noexecstack to fix glibc 2.41 compatibility

Explicitly pass `-Wl,-z,noexecstack` to the linker, to ensure that
`libpytorch_cpu.so` is compiled without an executable stack.  This is
necessary because the raw assembly in oneDNN triggers:

```
$BUILD_PREFIX/bin/../lib/gcc/x86_64-conda-linux-gnu/13.3.0/../../../../x86_64-conda-linux-gnu/bin/ld: warning: ittptmark64.S.o: missing .note.GNU-stack section implies executable stack
```

...and glibc 2.41 no longer permits loading libraries with executable
stack.

Fixes conda-forge#350

recipe/build.sh

@@ -40,6 +40,9 @@ export LDFLAGS="$(echo $LDFLAGS | sed 's/-Wl,--as-needed//g')"
 # error on osx-64.
 export LDFLAGS="$(echo $LDFLAGS | sed 's/-Wl,-dead_strip_dylibs//g')"
 export LDFLAGS_LD="$(echo $LDFLAGS_LD | sed 's/-dead_strip_dylibs//g')"
+# Explicitly force non-executable stack to fix compatibility with glibc 2.41, due to:
+# ittptmark64.S.o: missing .note.GNU-stack section implies executable stack
+LDFLAGS+=" -Wl,-z,noexecstack"
 if [[ "$c_compiler" == "clang" ]]; then
     export CXXFLAGS="$CXXFLAGS -Wno-deprecated-declarations -Wno-unknown-warning-option -Wno-error=unused-command-line-argument -Wno-error=vla-cxx-extension"
     export CFLAGS="$CFLAGS -Wno-deprecated-declarations -Wno-unknown-warning-option -Wno-error=unused-command-line-argument -Wno-error=vla-cxx-extension"