Rename a problematic test binary

Having a binary called printf is apparently asking for trouble,
so lets not do that.

http://bugzilla.gnome.org/show_bug.cgi?id=650078

glib/tests/Makefile.am

@@ -29,9 +29,9 @@ TEST_PROGS        += fileutils
 fileutils_SOURCES  = fileutils.c
 fileutils_LDADD	   = $(progs_ldadd)
 
-TEST_PROGS        += printf
-printf_SOURCES     = printf.c
-printf_LDADD       = $(progs_ldadd) -lm
+TEST_PROGS          += test-printf
+test_printf_SOURCES  = test-printf.c
+test_printf_LDADD    = $(progs_ldadd) -lm
 
 TEST_PROGS        += protocol
 protocol_SOURCES   = protocol.c