[tlbuild] dvisvgm fix for non-native build

[Ken Brown]

In svn rev 48527, the definition of HAVE_LIBGS was (inadvertently?) removed for 
non-native builds.  This prevents linking with libgs and causes the build to 
fail.  Reverting that portion of the revision fixes the problem:

Index: Build/source/texk/dvisvgm/configure.ac
===================================================================
--- Build/source/texk/dvisvgm/configure.ac      (revision 50896)
+++ Build/source/texk/dvisvgm/configure.ac      (working copy)
@@ -62,6 +62,9 @@
  AC_CHECK_HEADER([ghostscript/iapi.h],
         [AC_CHECK_LIB(gs, gsapi_revision,, [have_libgs=no])],
         [have_libgs=no])
+if test "x$have_libgs" = xyes; then
+  HAVE_LIBGS=1
+fi
  AS_IF([test "x$have_libgs" = "xno"],
         # Ghostscript not found, check for dlopen
         [AC_CHECK_LIB(dl, dlopen,,


Ken