Don't use included strlcpy/strlcat when already defined as macros

OS X 10.9 with Fortify has conflicting prototypes:

In file included from calmwm.c:36:
./calmwm.h:28:8: error: conflicting types for '__builtin___strlcat_chk' /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/secure/_string.h:111:3:
note:
      expanded from macro 'strlcat'
  __builtin___strlcat_chk (dest, src, len, __darwin_obsz (dest))