add three external/google-fonts projects:

external/google-fonts/coming-soon
external/google-fonts/dancing-script
external/google-fonts/carrois-gothic-sc
Add external/vixl

Change-Id: I633282d2a2ef43267edc0b5a9a250e700d713947
Add prebuilts/gcc/linux-x86/host/x86_64-linux-glibc2.11-4.[68]
Add external/ltrace to default.xml

Change-Id: Iea26eb8c84ecacf5e494af0da1ac3c6a84b89a8e
remove external/libnl-headers from the manifest

external/libnl-headers was part of system/core/libnl_2, which has
been replaced by external/libnl

Change-Id: I19b3bf9770ea5684bccee512686322d9f5dc033a
DO NOT MERGE: Revert "remove external/libnl-headers from the manifest"

This reverts commit fd1e90b3b1455615ff00c21dc90a0d4bfa21840e.

libnl_2 needs to stay in AOSP for now for compatibility with
GPL test builds.

Change-Id: I85365fb4b8931a998e564d30800a06343a47fdd8
Add GCC 4.9 for aarch64.
Adds external/libcxx and external/libcxxabi to manifest

Change-Id: I520b595d69834ff00140859e1d06dcc6d347e078