Port Jenkins script: compile

https://build.webmproject.org/jenkins/view/webp/job/libwebp__compile/

Change-Id: I646e3048cf4e3d8672b66838e31c7ccc53ced60f
Bug: b:185520507

infra/common.sh

@@ -48,6 +48,20 @@ make_build_dir() {
   mkdir -p "${build_dir}"
 }
 
+#######################################
+# Cleanup files from the build directory.
+# Args:
+#   $1 build directory
+# Globals:
+#   LIBWEBP_ROOT  repository's root path
+#######################################
+cleanup() {
+  # $1 is not completely removed to allow for binary artifacts to be
+  # extracted.
+  find "${1:?"Build directory not defined"}" \
+    \( -name "*.[ao]" -o -name "*.l[ao]" \) -exec rm -f {} +
+}
+
 #######################################
 # Setup ccache for toolchain.
 #######################################