Add top level build script for building packages.

ports/lua_ppapi/build.sh

Index: ports/lua_ppapi/build.sh
diff --git a/ports/lua_ppapi/build.sh b/ports/lua_ppapi/build.sh
old mode 100755
new mode 100644
index e2ec0d01698318458ef7c4f6d0eb29a5192324f9..b9fcf8a3f01c8fda37e95ab1326f9872be0c02df
--- a/ports/lua_ppapi/build.sh
+++ b/ports/lua_ppapi/build.sh
@@ -3,17 +3,14 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-source pkg_info
-source ../../build_tools/common.sh
-
+BUILD_DIR=${START_DIR}
 
 BuildStep() {
   # The sample is built using the NaCl SDK common.mk system.
   # We override $(OUTBASE) to force the build system to put
   # all its artifacts in ${NACL_PACKAGES_REPOSITORY} rather
   # than alongside the Makefile.
-  export OUTBASE=${NACL_PACKAGES_REPOSITORY}/${PACKAGE_DIR}
-  export OUTBASE=${NACL_PACKAGES_REPOSITORY}/${PACKAGE_DIR}
+  export OUTBASE=${SRC_DIR}
   export NACLPORTS_INCLUDE
   export NACLPORTS_PREFIX
   export NACL_PACKAGES_PUBLISH
@@ -36,7 +33,6 @@ BuildStep() {
     MAKEFLAGS+=" NACL_ARCH=${NACL_ARCH_ALT}"
   fi
   export MAKEFLAGS
-  ChangeDir ${START_DIR}
   DefaultBuildStep
 }
 
@@ -46,7 +42,3 @@ PackageInstall() {
   BuildStep
   InstallStep
 }
-
-
-PackageInstall
-exit 0