arm: add -D_FORTIFY_SOURCE=1 to the default cflags

Add additional compile and runtime buffer overflow detection to
Android. As of today, Android supports additional buffer overflow
detection for the following libc functions:

* memcpy
* memmove
* strcpy
* strcat
* strncpy
* strncat

Support for additional functions will be added to bionic libc in
future code changes.

Please see

for information on these features.

Change-Id: I1a281a4bac20009f4730dd8d8b798fa107576230
1 file changed