Don't use Autoconf quadrigraphs

[Bruno Haible]

Autoconf quadrigraphs are obsolete for a long time already.
No more need for them, definitely, in Autoconf >= 2.64.


2020-08-16  Bruno Haible  <bruno@clisp.org>

        Don't use Autoconf quadrigraphs.
        * m4/alloca.m4 (_AC_LIBOBJ_ALLOCA): Use '#' instead of the corresponding
        Autoconf quadrigraph.
        * m4/free.m4 (gl_FUNC_FREE): Likewise.
        * m4/getloadavg.m4 (gl_PREREQ_GETLOADAVG): Likewise.
        * m4/largefile.m4 (_AC_SYS_LARGEFILE_TEST_INCLUDES,
        _AC_SYS_LARGEFILE_MACRO_VALUE): Likewise.
        * m4/longlong.m4 (AC_TYPE_LONG_LONG_INT): Likewise.
        * m4/math_h.m4 (gl_MATH_H): Likewise.
        * m4/warn-on-use.m4 (gl_WARN_ON_USE_PREPARE): Likewise.

diff --git a/m4/alloca.m4 b/m4/alloca.m4
index b777f84..d841489 100644
--- a/m4/alloca.m4
+++ b/m4/alloca.m4
@@ -1,4 +1,4 @@
-# alloca.m4 serial 17
+# alloca.m4 serial 18
 dnl Copyright (C) 2002-2004, 2006-2007, 2009-2020 Free Software Foundation,
 dnl Inc.
 dnl This file is free software; the Free Software Foundation
@@ -102,7 +102,7 @@ AH_VERBATIM([STACK_DIRECTION],
         STACK_DIRECTION > 0 => grows toward higher addresses
         STACK_DIRECTION < 0 => grows toward lower addresses
         STACK_DIRECTION = 0 => direction of growth unknown */
-@%:@undef STACK_DIRECTION])dnl
+#undef STACK_DIRECTION])dnl
 AC_DEFINE_UNQUOTED(STACK_DIRECTION, $ac_cv_c_stack_direction)
 ])
 ])
diff --git a/m4/free.m4 b/m4/free.m4
index 02a8782..a62214c 100644
--- a/m4/free.m4
+++ b/m4/free.m4
@@ -24,12 +24,12 @@ AC_DEFUN([gl_FUNC_FREE],
        *)
          AC_COMPILE_IFELSE(
            [AC_LANG_PROGRAM(
-              [[@%:@include <unistd.h>]],
-              [[@%:@if _POSIX_VERSION < 199009L && \
+              [[#include <unistd.h>]],
+              [[#if _POSIX_VERSION < 199009L && \
                     (defined unix || defined _unix || defined _unix_ \
                      || defined __unix || defined __unix__)
-                  @%:@error "'free (NULL)' is not known to work"
-                @%:@endif]])],
+                  #error "'free (NULL)' is not known to work"
+                #endif]])],
            [gl_cv_func_free=yes],
            [gl_cv_func_free=no])
      esac
diff --git a/m4/getloadavg.m4 b/m4/getloadavg.m4
index 8e96965..9fe328e 100644
--- a/m4/getloadavg.m4
+++ b/m4/getloadavg.m4
@@ -7,7 +7,7 @@
 # gives unlimited permission to copy and/or distribute it,
 # with or without modifications, as long as this notice is preserved.
 
-#serial 9
+#serial 10
 
 # Autoconf defines AC_FUNC_GETLOADAVG, but that is obsolescent.
 # New applications should use gl_GETLOADAVG instead.
@@ -147,7 +147,7 @@ fi
 AC_CHECK_HEADERS([nlist.h],
 [AC_CHECK_MEMBERS([struct nlist.n_un.n_name],
                   [], [],
-                  [@%:@include <nlist.h>])
+                  [#include <nlist.h>])
  AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <nlist.h>]],
                    [[struct nlist x;
                     #ifdef HAVE_STRUCT_NLIST_N_UN_N_NAME
diff --git a/m4/largefile.m4 b/m4/largefile.m4
index f7140dd..f4c5d3a 100644
--- a/m4/largefile.m4
+++ b/m4/largefile.m4
@@ -30,12 +30,12 @@ m4_version_prereq([2.70], [] ,[
 # _AC_SYS_LARGEFILE_TEST_INCLUDES
 # -------------------------------
 m4_define([_AC_SYS_LARGEFILE_TEST_INCLUDES],
-[@%:@include <sys/types.h>
+[#include <sys/types.h>
  /* Check that off_t can represent 2**63 - 1 correctly.
     We can't simply define LARGE_OFF_T to be 9223372036854775807,
     since some C++ compilers masquerading as C compilers
     incorrectly reject 9223372036854775807.  */
-@%:@define LARGE_OFF_T (((off_t) 1 << 31 << 31) - 1 + ((off_t) 1 << 31 << 31))
+#define LARGE_OFF_T (((off_t) 1 << 31 << 31) - 1 + ((off_t) 1 << 31 << 31))
   int off_t_is_large[[(LARGE_OFF_T % 2147483629 == 721
                        && LARGE_OFF_T % 2147483647 == 1)
                       ? 1 : -1]];[]dnl
@@ -54,7 +54,7 @@ m4_define([_AC_SYS_LARGEFILE_MACRO_VALUE],
     [AC_LANG_PROGRAM([$5], [$6])],
     [$3=no; break])
   m4_ifval([$6], [AC_LINK_IFELSE], [AC_COMPILE_IFELSE])(
-    [AC_LANG_PROGRAM([@%:@define $1 $2
+    [AC_LANG_PROGRAM([#define $1 $2
 $5], [$6])],
     [$3=$2; break])
   $3=unknown
diff --git a/m4/longlong.m4 b/m4/longlong.m4
index e878488..c0ab70a 100644
--- a/m4/longlong.m4
+++ b/m4/longlong.m4
@@ -1,4 +1,4 @@
-# longlong.m4 serial 18
+# longlong.m4 serial 19
 dnl Copyright (C) 1999-2007, 2009-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -28,12 +28,12 @@ AC_DEFUN([AC_TYPE_LONG_LONG_INT],
           dnl nobody cross compiles for this platform as far as we know.
           AC_RUN_IFELSE(
             [AC_LANG_PROGRAM(
-               [[@%:@include <limits.h>
-                 @%:@ifndef LLONG_MAX
-                 @%:@ define HALF \
+               [[#include <limits.h>
+                 #ifndef LLONG_MAX
+                 # define HALF \
                           (1LL << (sizeof (long long int) * CHAR_BIT - 2))
-                 @%:@ define LLONG_MAX (HALF - 1 + HALF)
-                 @%:@endif]],
+                 # define LLONG_MAX (HALF - 1 + HALF)
+                 #endif]],
                [[long long int n = 1;
                  int i;
                  for (i = 0; ; i++)
diff --git a/m4/math_h.m4 b/m4/math_h.m4
index 44c810c..f259079 100644
--- a/m4/math_h.m4
+++ b/m4/math_h.m4
@@ -1,4 +1,4 @@
-# math_h.m4 serial 120
+# math_h.m4 serial 121
 dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -10,7 +10,7 @@ AC_DEFUN([gl_MATH_H],
   gl_CHECK_NEXT_HEADERS([math.h])
 
   AC_CACHE_CHECK([whether NAN macro works], [gl_cv_header_math_nan_works],
-    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[@%:@include <math.h>]],
+    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <math.h>]],
       [[/* Solaris 10 has a broken definition of NAN.  Other platforms
         fail to provide NAN, or provide it only in C99 mode; this
         test only needs to fail when NAN is provided but wrong.  */
@@ -25,7 +25,7 @@ AC_DEFUN([gl_MATH_H],
     REPLACE_NAN=1
   fi
   AC_CACHE_CHECK([whether HUGE_VAL works], [gl_cv_header_math_huge_val_works],
-    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[@%:@include <math.h>]],
+    [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <math.h>]],
       [[/* Solaris 10 has a broken definition of HUGE_VAL.  */
          double d = HUGE_VAL;
          return d == 0;]])],
diff --git a/m4/warn-on-use.m4 b/m4/warn-on-use.m4
index 3a692c7..1d2bcdf 100644
--- a/m4/warn-on-use.m4
+++ b/m4/warn-on-use.m4
@@ -1,4 +1,4 @@
-# warn-on-use.m4 serial 8
+# warn-on-use.m4 serial 9
 dnl Copyright (C) 2010-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -35,7 +35,7 @@ AC_DEFUN([gl_WARN_ON_USE_PREPARE],
        AC_CACHE_CHECK([whether $gl_func is declared without a macro],
          [gl_Symbol],
          [AC_COMPILE_IFELSE([AC_LANG_PROGRAM([$1],
-[[@%:@undef $gl_func
+[[#undef $gl_func
   (void) $gl_func;]])],
            [AS_VAR_SET([gl_Symbol], [yes])], [AS_VAR_SET([gl_Symbol], [no])])])
        AS_VAR_IF([gl_Symbol], [yes],