Export KYTHE_KZIP_ENCODING.

Bug: 146224091
Test: manual
Change-Id: I998a51565419b86a9f183c0f3228ce09d7b035c0
diff --git a/build_kzip.bash b/build_kzip.bash
index 329825a..008030f 100755
--- a/build_kzip.bash
+++ b/build_kzip.bash
@@ -14,6 +14,7 @@
 
 : ${BUILD_NUMBER:=$(uuidgen)}
 : ${KYTHE_KZIP_ENCODING:=proto}
+export KYTHE_KZIP_ENCODING
 
 # The extraction might fail for some source files, so run with -k and then check that
 # sufficiently many files were generated.