Whitespace cleanup of all Makefiles*

- some of the %.clean rules in the test-suite Makefiles were using a single tab
  as an empty rule, dangerous! I've replaced these with the safer '@exit 0'.

Examples/test-suite/tcl/Makefile.in

@@ -4,7 +4,7 @@
 
 LANGUAGE     = tcl
 TCLSH        = tclsh
-SCRIPTSUFFIX = _runme.tcl 
+SCRIPTSUFFIX = _runme.tcl
 srcdir       = @srcdir@
 top_srcdir   = @top_srcdir@
 top_builddir = @top_builddir@
@@ -27,7 +27,7 @@ include $(srcdir)/../common.mk
 # none!
 
 # Rules for the different types of tests
-%.cpptest: 
+%.cpptest:
 	$(setup)
 	+$(swig_and_compile_cpp)
 	$(run_testcase)
@@ -37,7 +37,7 @@ include $(srcdir)/../common.mk
 	+$(swig_and_compile_c)
 	$(run_testcase)
 
-%.multicpptest: 
+%.multicpptest:
 	$(setup)
 	+$(swig_and_compile_multi_cpp)
 	$(run_testcase)
@@ -51,7 +51,7 @@ run_testcase = \
 
 # Clean
 %.clean:
-	
+	@exit 0
 
 clean:
 	$(MAKE) -f $(top_builddir)/$(EXAMPLES)/Makefile tcl_clean