+ else
+ $4])
+ fi],[enableval=$5 ifelse([$4],,,[
+ $4
+])dnl
+])])dnl
+dnl ---------------------------------------------------------------------------
+dnl CF_C11_NORETURN version: 3 updated: 2021/03/28 11:36:23
+dnl ---------------
+AC_DEFUN([CF_C11_NORETURN],
+[
+AC_MSG_CHECKING(if you want to use C11 _Noreturn feature)
+CF_ARG_ENABLE(stdnoreturn,
+ [ --enable-stdnoreturn enable C11 _Noreturn feature for diagnostics],
+ [enable_stdnoreturn=yes],
+ [enable_stdnoreturn=no])
+AC_MSG_RESULT($enable_stdnoreturn)
+
+if test $enable_stdnoreturn = yes; then
+AC_CACHE_CHECK([for C11 _Noreturn feature], cf_cv_c11_noreturn,
+ [AC_TRY_COMPILE([
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdnoreturn.h>
+static _Noreturn void giveup(void) { exit(0); }
+ ],
+ [if (feof(stdin)) giveup()],
+ cf_cv_c11_noreturn=yes,
+ cf_cv_c11_noreturn=no)
+ ])
+else
+ cf_cv_c11_noreturn=no,
+fi
+
+if test "$cf_cv_c11_noreturn" = yes; then
+ AC_DEFINE(HAVE_STDNORETURN_H, 1,[Define if <stdnoreturn.h> header is available and working])
+ AC_DEFINE_UNQUOTED(STDC_NORETURN,_Noreturn,[Define if C11 _Noreturn keyword is supported])
+ HAVE_STDNORETURN_H=1
+else
+ HAVE_STDNORETURN_H=0
+fi
+
+AC_SUBST(HAVE_STDNORETURN_H)
+AC_SUBST(STDC_NORETURN)
+])dnl
+dnl ---------------------------------------------------------------------------
+dnl CF_CC_ENV_FLAGS version: 10 updated: 2020/12/31 18:40:20
+dnl ---------------
+dnl Check for user's environment-breakage by stuffing CFLAGS/CPPFLAGS content
+dnl into CC. This will not help with broken scripts that wrap the compiler
+dnl with options, but eliminates a more common category of user confusion.
+dnl
+dnl In particular, it addresses the problem of being able to run the C
+dnl preprocessor in a consistent manner.
+dnl
+dnl Caveat: this also disallows blanks in the pathname for the compiler, but
+dnl the nuisance of having inconsistent settings for compiler and preprocessor
+dnl outweighs that limitation.
+AC_DEFUN([CF_CC_ENV_FLAGS],
+[
+# This should have been defined by AC_PROG_CC
+: "${CC:=cc}"
+
+AC_MSG_CHECKING(\$CFLAGS variable)
+case "x$CFLAGS" in
+(*-[[IUD]]*)
+ AC_MSG_RESULT(broken)
+ AC_MSG_WARN(your environment uses the CFLAGS variable to hold CPPFLAGS options)
+ cf_flags="$CFLAGS"
+ CFLAGS=
+ for cf_arg in $cf_flags
+ do
+ CF_ADD_CFLAGS($cf_arg)
+ done
+ ;;
+(*)
+ AC_MSG_RESULT(ok)
+ ;;
+esac
+
+AC_MSG_CHECKING(\$CC variable)
+case "$CC" in
+(*[[\ \ ]]-*)
+ AC_MSG_RESULT(broken)
+ AC_MSG_WARN(your environment uses the CC variable to hold CFLAGS/CPPFLAGS options)
+ # humor him...
+ cf_prog=`echo "$CC" | sed -e 's/ / /g' -e 's/[[ ]]* / /g' -e 's/[[ ]]*[[ ]]-[[^ ]].*//'`
+ cf_flags=`echo "$CC" | ${AWK:-awk} -v prog="$cf_prog" '{ printf("%s", [substr]([$]0,1+length(prog))); }'`
+ CC="$cf_prog"
+ for cf_arg in $cf_flags
+ do
+ case "x$cf_arg" in
+ (x-[[IUDfgOW]]*)
+ CF_ADD_CFLAGS($cf_arg)
+ ;;
+ (*)
+ CC="$CC $cf_arg"
+ ;;
+ esac
+ done
+ CF_VERBOSE(resulting CC: '$CC')
+ CF_VERBOSE(resulting CFLAGS: '$CFLAGS')
+ CF_VERBOSE(resulting CPPFLAGS: '$CPPFLAGS')
+ ;;
+(*)
+ AC_MSG_RESULT(ok)
+ ;;
+esac