[alg.c.library,c.math.fpclass,cmath.syn] Use \xrefc macro

and augment the automatic checks to flag literal 'ISO C'.

Author: jensmaurer

source/algorithms.tex

@@ -10968,5 +10968,4 @@
 Any exception thrown by \tcode{compar}\iref{res.on.exception.handling}.
 \end{itemdescr}
 
-\xref
-ISO C 7.22.5.
+\xrefc{7.22.5}

source/numerics.tex

@@ -9949,8 +9949,7 @@
 \tcode{abs} is exempted from these rules in order to stay compatible with C.
 \end{note}
 
-\xref
-ISO C 7.12
+\xrefc{7.12}
 
 \rSec2[c.math.abs]{Absolute values}
 
@@ -10047,8 +10046,7 @@
 corresponding names defined in the C standard library.
 Each function is overloaded for the three floating-point types.
 
-\xref
-ISO C 7.12.3, 7.12.4
+\xrefc{7.12.3, 7.12.4}
 
 \rSec2[sf.cmath]{Mathematical special functions}%
 

tools/check-source.sh

@@ -71,6 +71,10 @@ grep -n "// not defined" $texfiles |
 grep -n '^[^%]*[^{"]C++[^"}]' $texfiles |
     fail 'use \Cpp{} instead' || failed=1
 
+# Use \xrefc instead of "ISO C x.y.z"
+grep -n "^ISO C [0-9]*\." $texfiles |
+    fail 'use \\xrefc instead' || failed=1
+
 # Library element introducer followed by stuff.
 grep -ne '^\\\(constraints\|mandates\|expects\|effects\|sync\|ensures\|returns\|throws\|complexity\|remarks\|errors\).\+$' $texlibdesc |
     fail 'stuff after library element' || failed=1