--- a/configure	Mon Oct 01 15:29:54 2018 +0100
+++ b/configure	Mon Oct 01 15:30:49 2018 +0100
@@ -150,9 +150,8 @@
       ;;
    --ostype)
 	# TODO make this a switch?
-      OSTYPE="$value"
-      OSTYPE_SET=yes
-      if [ "$OSTYPE" = "debian" ]; then
+      OSPRESET="$value"
+      if [ "$OSPRESET" = "debian" ]; then
          if [ "$LUA_SUFFIX_SET" != "yes" ]; then
             LUA_SUFFIX="5.1";
             LUA_SUFFIX_SET=yes
@@ -165,7 +164,7 @@
          LUA_INCDIR_SET=yes
          CFLAGS="$CFLAGS -ggdb"
       fi
-      if [ "$OSTYPE" = "macosx" ]; then
+      if [ "$OSPRESET" = "macosx" ]; then
          LUA_INCDIR=/usr/local/include;
          LUA_INCDIR_SET=yes
          LUA_LIBDIR=/usr/local/lib
@@ -173,14 +172,14 @@
          CFLAGS="$CFLAGS -mmacosx-version-min=10.3"
          LDFLAGS="-bundle -undefined dynamic_lookup"
       fi
-      if [ "$OSTYPE" = "linux" ]; then
+      if [ "$OSPRESET" = "linux" ]; then
          LUA_INCDIR=/usr/local/include;
          LUA_INCDIR_SET=yes
          LUA_LIBDIR=/usr/local/lib
          LUA_LIBDIR_SET=yes
          CFLAGS="$CFLAGS -ggdb"
       fi
-      if [ "$OSTYPE" = "freebsd" -o "$OSTYPE" = "openbsd" ]; then
+      if [ "$OSPRESET" = "freebsd" -o "$OSPRESET" = "openbsd" ]; then
          LUA_INCDIR="/usr/local/include/lua51"
          LUA_INCDIR_SET=yes
          CFLAGS="-Wall -fPIC -I/usr/local/include"
@@ -192,11 +191,11 @@
          CC=cc
          LD=ld
       fi
-      if [ "$OSTYPE" = "openbsd" ]; then
+      if [ "$OSPRESET" = "openbsd" ]; then
          LUA_INCDIR="/usr/local/include";
          LUA_INCDIR_SET="yes"
       fi
-      if [ "$OSTYPE" = "netbsd" ]; then
+      if [ "$OSPRESET" = "netbsd" ]; then
          LUA_INCDIR="/usr/pkg/include/lua-5.1"
          LUA_INCDIR_SET=yes
          LUA_LIBDIR="/usr/pkg/lib/lua/5.1"
@@ -204,7 +203,7 @@
          CFLAGS="-Wall -fPIC -I/usr/pkg/include"
          LDFLAGS="-L/usr/pkg/lib -Wl,-rpath,/usr/pkg/lib -shared"
       fi
-      if [ "$OSTYPE" = "pkg-config" ]; then
+      if [ "$OSPRESET" = "pkg-config" ]; then
          if [ "$LUA_SUFFIX_SET" != "yes" ]; then
             LUA_SUFFIX="5.1";
             LUA_SUFFIX_SET=yes