tox.ini: support macos style find

macos doesn't ship GNU find, and doesn't have the `-executable`
filter, so fall back to `-perm +111` on mac plaforms.

Author: masenf

tox.ini

@@ -2,13 +2,19 @@
 minversion = 3.7.0
 skipsdist = true
 allowlist_external = /usr/bin/env
-envlist = py3
+envlist = py3-{linux,mac}
 
 [testenv]
+platform =
+    linux: linux
+    mac: darwin
 passenv = OUTPUT REPEATERBOOK_USER REPEATERBOOK_PASSWD
+setenv =
+    !mac: FIND_OPTS = -executable
+    mac: FIND_OPTS = -perm '+111'
 deps =
     dzcb~=0.1
 commands =
     /usr/bin/env find {toxinidir}/input \
         -name "generate.sh" \
-        -executable -exec \{\} ;
+        {env:FIND_OPTS} -exec \{\} ;