+
+CLANG_VERSION=none
+
+if test "x$ifelse([$2],,CLANG_COMPILER,[$2])" = "xyes" ; then
+ case "$CC" in
+ (c[[1-9]][[0-9]]|*/c[[1-9]][[0-9]])
+ AC_MSG_WARN(replacing broken compiler alias $CC)
+ CFLAGS="$CFLAGS -std=`echo "$CC" | sed -e 's%.*/%%'`"
+ CC=clang
+ ;;
+ esac
+
+ AC_MSG_CHECKING(version of $CC)
+ CLANG_VERSION="`$CC --version 2>/dev/null | sed -e '2,$d' -e 's/^.*(CLANG[[^)]]*) //' -e 's/^.*(Debian[[^)]]*) //' -e 's/^[[^0-9.]]*//' -e 's/[[^0-9.]].*//'`"
+ test -z "$CLANG_VERSION" && CLANG_VERSION=unknown
+ AC_MSG_RESULT($CLANG_VERSION)
+
+ for cf_clang_opt in \
+ -Qunused-arguments \
+ -Wno-error=implicit-function-declaration
+ do
+ AC_MSG_CHECKING(if option $cf_clang_opt works)
+ cf_save_CFLAGS="$CFLAGS"
+ CFLAGS="$CFLAGS $cf_clang_opt"
+ AC_TRY_LINK([
+ #include <stdio.h>],[
+ printf("hello!\\n");],[
+ cf_clang_optok=yes],[
+ cf_clang_optok=no])
+ AC_MSG_RESULT($cf_clang_optok)
+ CFLAGS="$cf_save_CFLAGS"
+ if test "$cf_clang_optok" = yes; then
+ CF_VERBOSE(adding option $cf_clang_opt)
+ CF_APPEND_TEXT(CFLAGS,$cf_clang_opt)
+ fi
+ done
+fi
+])
+dnl ---------------------------------------------------------------------------
+dnl CF_CONST_X_STRING version: 6 updated: 2021/01/01 13:31:04
+dnl -----------------
+dnl The X11R4-X11R6 Xt specification uses an ambiguous String type for most
+dnl character-strings.
+dnl
+dnl It is ambiguous because the specification accommodated the pre-ANSI
+dnl compilers bundled by more than one vendor in lieu of providing a standard C
+dnl compiler other than by costly add-ons. Because of this, the specification
+dnl did not take into account the use of const for telling the compiler that
+dnl string literals would be in readonly memory.
+dnl
+dnl As a workaround, one could (starting with X11R5) define XTSTRINGDEFINES, to
+dnl let the compiler decide how to represent Xt's strings which were #define'd.
+dnl That does not solve the problem of using the block of Xt's strings which
+dnl are compiled into the library (and is less efficient than one might want).
+dnl
+dnl Xt specification 7 introduces the _CONST_X_STRING symbol which is used both
+dnl when compiling the library and compiling using the library, to tell the
+dnl compiler that String is const.
+AC_DEFUN([CF_CONST_X_STRING],
+[
+AC_REQUIRE([AC_PATH_XTRA])
+
+CF_SAVE_XTRA_FLAGS([CF_CONST_X_STRING])
+
+AC_TRY_COMPILE(
+[
+#include <stdlib.h>
+#include <X11/Intrinsic.h>
+],
+[String foo = malloc(1); (void)foo],[
+
+AC_CACHE_CHECK(for X11/Xt const-feature,cf_cv_const_x_string,[
+ AC_TRY_COMPILE(
+ [
+#define _CONST_X_STRING /* X11R7.8 (perhaps) */
+#undef XTSTRINGDEFINES /* X11R5 and later */
+#include <stdlib.h>
+#include <X11/Intrinsic.h>
+ ],[String foo = malloc(1); *foo = 0],[
+ cf_cv_const_x_string=no
+ ],[
+ cf_cv_const_x_string=yes
+ ])