Fix cross-compiling by replacing hardcoded -L/usr/X11R6/lib

Bug #193062 r=peterl a=asa

modules/plugin/base/src/Makefile.in

@@ -145,7 +145,7 @@ EXTRA_DSO_LDOPTS += -lgtkxtbin $(XLDFLAGS) $(XT_LIBS) $(MOZ_GTK2_LIBS) $(XLIBS)
 endif           #MOZ_ENABLE_GTK2
 
 ifdef MOZ_ENABLE_XLIB
-EXTRA_DSO_LDOPTS += -lxlibxtbin -lxlibrgb -L/usr/X11R6/lib $(XT_LIBS)
+EXTRA_DSO_LDOPTS += -lxlibxtbin -lxlibrgb $(XLDFLAGS) $(XT_LIBS)
 ifndef MOZ_MONOLITHIC_TOOLKIT
 CXXFLAGS        += $(MOZ_XLIB_CFLAGS)
 CFLAGS          += $(MOZ_XLIB_CFLAGS)

modules/plugin/tools/sdk/samples/basic/unix/Makefile.in

@@ -43,7 +43,7 @@ include $(topsrcdir)/config/rules.mk
 
 DEFINES += -DMOZILLA_STRICT_API
 
-EXTRA_DSO_LDOPTS +=  -L/usr/lib -L/usr/X11R6/lib  -rdynamic  -lXi -lXext -lX11 -lm -lXt
+EXTRA_DSO_LDOPTS +=  $(XLDFLAGS) -rdynamic  -lXi -lXext -lX11 -lm -lXt
 
 INSTALL_PLUGIN	= $(CONFIG_TOOLS)/nsinstall -R 
 INSTALL = true

modules/plugin/tools/sdk/samples/scriptable/unix/Makefile.in

@@ -46,7 +46,7 @@ include $(topsrcdir)/config/rules.mk
 
 DEFINES += -DMOZILLA_STRICT_API
 
-EXTRA_DSO_LDOPTS +=  -L/usr/lib -L/usr/X11R6/lib  -rdynamic  -lXi -lXext -lX11 -lm -lXt
+EXTRA_DSO_LDOPTS +=  $(XLDFLAGS) -rdynamic  -lXi -lXext -lX11 -lm -lXt
 
 INSTALL_PLUGIN	= $(CONFIG_TOOLS)/nsinstall -R 
 INSTALL = true

modules/plugin/tools/sdk/samples/simple/Makefile.in

@@ -53,7 +53,7 @@ include $(topsrcdir)/config/rules.mk
 DEFINES += -DMOZILLA_STRICT_API
 
 ifeq ($(OS_ARCH),Linux)
-EXTRA_DSO_LDOPTS +=  -L/usr/lib -L/usr/X11R6/lib  -rdynamic  -lXi -lXext -lX11 -lm -lXt
+EXTRA_DSO_LDOPTS +=  $(XLDFLAGS) -rdynamic  -lXi -lXext -lX11 -lm -lXt
 endif
 
 LOCAL_INCLUDES = -I./$(XPIDL_GEN_DIR) \