Android: Set GOMA_COMPILER_PROXY_THREADS to a reasonable value

build/android/envsetup.sh

Index: build/android/envsetup.sh
diff --git a/build/android/envsetup.sh b/build/android/envsetup.sh
index f9e3e5ede1f0b74e5c21f1d95a2108ae5a6613d9..cacfafc79c60eb7c50e27a9c070aaf0dfab43bc8 100755
--- a/build/android/envsetup.sh
+++ b/build/android/envsetup.sh
@@ -143,6 +143,14 @@ fi
 ANDROID_GOMA_WRAPPER=""
 if [[ -d $GOMA_DIR ]]; then
   ANDROID_GOMA_WRAPPER="$GOMA_DIR/gomacc"
+  num_cores="$(grep --count ^processor /proc/cpuinfo)"
+# Goma is IO-ish you want more threads than you have cores.
+  let goma_threads=num_cores*2
+  if [ -z "${GOMA_COMPILER_PROXY_THREADS}" -a "${goma_threads}" -gt 16 ]; then
+# The default is 16 threads, if the machine has many cores we crank it up a bit
+    GOMA_COMPILER_PROXY_THREADS="${goma_threads}"
+    export GOMA_COMPILER_PROXY_THREADS
+  fi
 fi
 export ANDROID_GOMA_WRAPPER