maint.mk: improve sc_prohibit_intprops_without_use

* top/maint.mk (_intprops_names): Don't hard-code the list of
symbol names.  Instead, derive it on the fly.

ChangeLog

@@ -1,3 +1,9 @@
+2016-12-30  Jim Meyering  <meyering@fb.com>
+
+	maint.mk: improve sc_prohibit_intprops_without_use
+	* top/maint.mk (_intprops_names): Don't hard-code the list of
+	symbol names.  Instead, derive it on the fly.
+
 2016-12-30  Paul Eggert  <eggert@cs.ucla.edu>
 
 	dfa: shorten sbit, success

top/maint.mk

@@ -657,18 +657,14 @@ sc_prohibit_strings_without_use:
 	re='\<(strn?casecmp|ffs(ll)?)\>'				\
 	  $(_sc_header_without_use)
 
-# Get the list of symbol names with this:
-# perl -lne '/^# *define ([A-Z]\w+)\(/ and print $1' lib/intprops.h|fmt
-_intprops_names =							\
-  TYPE_IS_INTEGER TYPE_SIGNED EXPR_SIGNED TYPE_WIDTH TYPE_MINIMUM	\
-  TYPE_MAXIMUM INT_BITS_STRLEN_BOUND INT_STRLEN_BOUND INT_BUFSIZE_BOUND	\
-  INT_ADD_RANGE_OVERFLOW INT_SUBTRACT_RANGE_OVERFLOW			\
-  INT_NEGATE_RANGE_OVERFLOW INT_MULTIPLY_RANGE_OVERFLOW			\
-  INT_DIVIDE_RANGE_OVERFLOW INT_REMAINDER_RANGE_OVERFLOW		\
-  INT_LEFT_SHIFT_RANGE_OVERFLOW INT_ADD_OVERFLOW INT_SUBTRACT_OVERFLOW	\
-  INT_NEGATE_OVERFLOW INT_NEGATE_OVERFLOW INT_MULTIPLY_OVERFLOW		\
-  INT_DIVIDE_OVERFLOW INT_REMAINDER_OVERFLOW INT_LEFT_SHIFT_OVERFLOW	\
-  INT_ADD_WRAPV INT_SUBTRACT_WRAPV INT_MULTIPLY_WRAPV
+# Extract the raw list of symbol names with this:
+gl_extract_define_simple = \
+  /^\# *define ([A-Z]\w+)\(/ and print $$1
+# Filter out duplicates and convert to a space-separated list:
+_intprops_names := \
+  $(shell f=$(gnulib_dir)/lib/intprops.h;				\
+    perl -lne '$(gl_extract_define_simple)' $$f | sort -u | tr '\n' ' ')
+# Remove trailing space and convert to a regular expression:
 _intprops_syms_re = $(subst $(_sp),|,$(strip $(_intprops_names)))
 # Prohibit the inclusion of intprops.h without an actual use.
 sc_prohibit_intprops_without_use: