* builds/unix/configure.raw (FT_DEMO_CFLAGS): Pass `-DHAVE-LIBRSVG`.

This helps in decoupling library support from `pkg-config` for other
platforms.
diff --git a/builds/unix/configure.raw b/builds/unix/configure.raw
index 08ec21a..e9eb0ee 100644
--- a/builds/unix/configure.raw
+++ b/builds/unix/configure.raw
@@ -538,7 +538,7 @@
 FT_DEMO_LDFLAGS="$LIB_CLOCK_GETTIME"
 
 if test "$have_librsvg" != no; then
-  FT_DEMO_CFLAGS="$FT_DEMO_CFLAGS $LIBRSVG_CFLAGS"
+  FT_DEMO_CFLAGS="$FT_DEMO_CFLAGS $LIBRSVG_CFLAGS -DHAVE_LIBRSVG"
   FT_DEMO_LDFLAGS="$FT_DEMO_LDFLAGS $LIBRSVG_LIBS"
 fi