Enable NX protections

Add -Wa,--noexecstack and -Wl,-z,noexecstack as default
flags when compiling host-side applications.  This enables
NX protections, which prevent code from executing on the
stack or heap.  NX protections make exploiting memory
corruption issues more challenging and is an important
security feature.

Change-Id: Iae580abe887e01f9029ec2a4e0fc0aae496724a4
Fix regex for finding symbol data.

The new output of debuggerd removed a space between the #00 and the rest
of the line. The regex is very restrictive, so fixing it to handle the new
output.

Change-Id: I5259ae1e56a351608b330dfd858a2021e6d89358
Add an explicit definition of __ANDROID__=1

Once the aarch64 toolchain is refreshed this will be removed.
Also removed some CFLAG duplications.

Change-Id: I42fd86931263af82042ea696196fb25e948fe9cb
Merge "Add an explicit definition of __ANDROID__=1"
Merge "Fix regex for finding symbol data."
Merge "Enable NX protections"
Merge branch 'master' of https://android.googlesource.com/platform/build into HEAD