Rename OS/400 free-form header.

os400/make.sh

diff --git a/os400/make.sh b/os400/make.sh
index c24afe9..e9643f5 100644
--- a/os400/make.sh
+++ b/os400/make.sh
@@ -251,7 +251,7 @@
         system "CHGPFM FILE(${TARGETLIB}/H) MBR(${MBR}) SRCTYPE(RPGLE)"
 fi
 
-HFILE="${SCRIPTDIR}/zlibfree"
+HFILE="${SCRIPTDIR}/zlibfree.rpgle"
 MBR="ZLIBFREE"
 DEST="${SRCPF}/${MBR}.MBR"
 

os400/zlibfree.rpgle

diff --git a/os400/zlibfree.inc b/os400/zlibfree.rpgle
similarity index 100%
rename from os400/zlibfree.inc
rename to os400/zlibfree.rpgle