Fixed build error of "Syntax error: redirection unexpected".

build.sh

@@ -1,6 +1,12 @@
-# !/bin/bash
+# !/bin/sh
 # set -x
 
+echo "
+zgacertsutil.js
+zgapdfcryptor.js
+zgapdfsigner.js
+zgaindex.js
+" | {
 	OUTFLDR=dist
 	if [ -d ${OUTFLDR} ]
 	then
@@ -8,7 +14,6 @@ then
 	else
 		mkdir ${OUTFLDR}
 	fi
-
 	GCCOPT="--charset UTF-8 --compilation_level SIMPLE_OPTIMIZATIONS --warning_level VERBOSE"
 	GCCEXT="--externs closure/google-ext.js --externs closure/forge-ext.js --externs closure/pdflib-ext.js --externs closure/zb-externs.js"
 	jss=""
@@ -31,17 +36,13 @@ do
 				fi
 			fi
 		fi
-done <<< "
-zgacertsutil.js
-zgapdfcryptor.js
-zgapdfsigner.js
-zgaindex.js
-"
+	done
 	npx google-closure-compiler ${GCCOPT} ${GCCEXT} ${jss} --js_output_file ${OUTFLDR}/zgapdfsigner.min.js
 	if [ $? -ne 0 ]
 	then
 		echo "google-closure-compiler failed."
 		exit 20
 	fi
-
 	exit 0
+}
+exit $?