add config_vcl to control DevicePixel coordinate base type

The eventual goal is to make vcl capable of handling a backend
that use double instead of sal_Int32 as its base type
for device coordinate.

Change-Id: I6174f1f4afe00992b95c9163bc21dd54fec98631

config_host/config_vcl.h.in

+/*
+
+Settings about vcl
+*/
+
+#ifndef CONFIG_VCL_H
+#define CONFIG_VCL_H
+
+/* nature of the device pixel coordinate system
+ * either use sal_Int32 or double for coordinates
+ */
+#define VCL_FLOAT_DEVICE_PIXEL 0
+
+#endif

configure.ac

@@ -10076,6 +10076,18 @@ if ! "$TOUCH" -h warn 2>/dev/null > /dev/null; then
     AC_MSG_ERROR([touch version with -h option support is required to build, please install it and make sure it is the one found first in PATH],,)
 fi
 
+dnl ===================================================================
+dnl Set vcl option: coordinate device in double or sal_Int32
+dnl ===================================================================
+
+AC_MSG_CHECKING([Type to use for Device Pixel coordinates])
+if test "$_os" = "Darwin" -o  $_os = iOS ; then
+    AC_DEFINE(VCL_FLOAT_DEVICE_PIXEL)
+    AC_MSG_RESULT([double])
+else
+    AC_MSG_RESULT([sal_Int32])
+fi
+
 dnl ===================================================================
 dnl Test which vclplugs have to be built.
 dnl ===================================================================
@@ -13053,6 +13065,7 @@ AC_CONFIG_HEADERS([config_host/config_options.h])
 AC_CONFIG_HEADERS([config_host/config_test.h])
 AC_CONFIG_HEADERS([config_host/config_telepathy.h])
 AC_CONFIG_HEADERS([config_host/config_typesizes.h])
+AC_CONFIG_HEADERS([config_host/config_vcl.h])
 AC_CONFIG_HEADERS([config_host/config_vclplug.h])
 AC_CONFIG_HEADERS([config_host/config_version.h])
 AC_CONFIG_HEADERS([config_host/config_oauth2.h])

include/vcl/outdev.hxx

@@ -20,6 +20,8 @@
 #ifndef INCLUDED_VCL_OUTDEV_HXX
 #define INCLUDED_VCL_OUTDEV_HXX
 
+#include <config_vcl.h>
+
 #include <tools/gen.hxx>
 #include <tools/solar.h>
 #include <tools/rc.hxx>