configure.ac: Check for libGLU for screensaver

https://bugs.freedesktop.org/show_bug.cgi?id=56376

clients/Makefile.am

@@ -174,6 +174,7 @@ full_gl_client_programs = gears
 gears_SOURCES = gears.c
 gears_LDADD = $(toolkit_libs)
 
+if HAVE_GLU
 screensaver = weston-screensaver
 weston_screensaver_SOURCES =			\
 	wscreensaver.c				\
@@ -184,7 +185,10 @@ weston_screensaver_SOURCES =			\
 	wscreensaver-glue.h			\
 	glmatrix.c				\
 	matrix3.xpm
-weston_screensaver_LDADD = $(toolkit_libs) -lGLU
+weston_screensaver_LDADD = $(toolkit_libs) $(GLU_LIBS)
+weston_screensaver_CFLAGS = $(toolkit_libs) $(GLU_CFLAGS)
+endif
+
 endif
 
 @wayland_scanner_rules@

configure.ac

@@ -206,6 +206,10 @@ if test x$enable_weston_launch == xyes; then
   WESTON_LAUNCH_LIBS="$WESTON_LAUNCH_LIBS -lpam"
 fi
 
+PKG_CHECK_MODULES(GLU, [glu], [have_glu=yes], [have_glu=no])
+AM_CONDITIONAL(HAVE_GLU, test "x$have_glu" = "xyes")
+
+
 AM_CONDITIONAL(HAVE_POPPLER, test "x$have_poppler" = "xyes")
 
 AM_CONDITIONAL(BUILD_FULL_GL_CLIENTS,