tests: rename a syntax-check

* cfg.mk (sc_prohibit_always-defined_macros): Rename from
sc_always_defined_macros.
* .x-sc_prohibit_always-defined_macros: New file, renamed from...
* .x-sc_always_defined_macros: ...removed.
* Makefile.am (syntax_check_exceptions): Rename here, too.

Makefile.am

@@ -41,12 +41,12 @@ changelog_etc =				\
 
 syntax_check_exceptions =		\
   .x-sc_GPL_version			\
-  .x-sc_always_defined_macros		\
   .x-sc_error_message_uppercase		\
   .x-sc_file_system			\
   .x-sc_obsolete_symbols		\
   .x-sc_po_check			\
   .x-sc_program_name			\
+  .x-sc_prohibit_always-defined_macros	\
   .x-sc_prohibit_atoi_atof		\
   .x-sc_prohibit_empty_lines_at_EOF	\
   .x-sc_prohibit_fail_0			\

cfg.mk

@@ -140,7 +140,7 @@ define gl_trap_
 endef
 
 # Don't define macros that we already get from gnulib header files.
-sc_always_defined_macros: .re-defmac
+sc_prohibit_always-defined_macros: .re-defmac
 	@if test -d $(gnulib_dir); then					\
 	  trap 'rc=$$?; rm -f .re-defmac; exit $$rc' 0;			\
 	  $(gl_trap_);							\