Fix the path for installing GTK3 libraries.

Signed-off-by: Slávek Banko <slavek.banko@axis.cz>
(cherry picked from commit b0c586879b)

configure.in.in

@@ -79,6 +79,7 @@ if test -n "$PKGCONFIG"; then
      GTK3_CFLAGS="`$PKGCONFIG gtk+-3.0 --cflags`"
      GTK3_PREFIX=`$PKG_CONFIG --variable=prefix gtk+-3.0`
      GTK3_VERSION=`$PKG_CONFIG --variable=gtk_binary_version gtk+-3.0`
+     GTK3_LIBDIR=`$PKG_CONFIG --variable=libdir gtk+-3.0`
 
      AC_DEFINE_UNQUOTED(HAVE_GTK3, 1, [Defines if your system has the GTK3 library])
   fi
@@ -99,6 +100,7 @@ AC_SUBST(GTK3_LIBS)
 AC_SUBST(GTK3_CFLAGS)
 AC_SUBST(GTK3_RPATH)
 AC_SUBST(GTK3_PREFIX)
+AC_SUBST(GTK3_LIBDIR)
 AC_SUBST(GTK3_VERSION)
 
 AM_CONDITIONAL(have_openexr, test -n "$GTK3_LIBS")

tdegtk/Makefile.am

@@ -36,7 +36,7 @@ source_c = \
 	$(srcdir)/tdegtk-baseengine.cpp \
 	$(srcdir)/tdegtk-theme.cpp
 
-enginedir = $(GTK3_PREFIX)/lib/gtk-3.0/$(GTK3_VERSION)/theming-engines
+enginedir = $(GTK3_PREFIX)/$(GTK3_LIBDIR)/gtk-3.0/$(GTK3_VERSION)/theming-engines
 engine_LTLIBRARIES = libtdegtk.la
 
 libtdegtk_la_SOURCES = $(source_h) $(source_c)