workaround an armv6 gcc 4.7 bug

this fixes com.android.phone getting a SIGBUS on startup due to mmap'd
tzdata reads that always crash in this libcore code.
gcc 4.8 works without issue and 4.6 worked fine with cm10.1, so this
workaround has been made specific to just gcc 4.7.

Change-Id: Ide3b33dd8bdbb1e0f1a91b65ba21c7aa8e276af5