Add patch for ax_c_float_words_bigendian.m4 to autoconf-archive

autoconf/Dockerfile

@@ -30,8 +30,12 @@ RUN curl https://ftp.gnu.org/gnu/automake/automake-${AUTOMAKE_VERSION}.tar.gz |
     && ./configure --prefix=/usr/local \
     && make \
     && make install
-RUN curl https://ftp.gnu.org/gnu/autoconf-archive/autoconf-archive-${AUTOCONF_ARCHIVE_VERSION}.tar.xz | xz -cd - | tar -xf - \
+# We can get rid of the ax_c_float_words_bigendian.m4 patch when a new version
+# of autoconf-archive is released.
+COPY ax_c_float_words_bigendian.diff .
+RUN PATCH_VERBOSE=1 curl https://ftp.gnu.org/gnu/autoconf-archive/autoconf-archive-${AUTOCONF_ARCHIVE_VERSION}.tar.xz | xz -cd - | tar -xf - \
     && cd autoconf-archive-${AUTOCONF_ARCHIVE_VERSION} \
+    && patch -p1 -i ../ax_c_float_words_bigendian.diff \
     && ./configure --prefix=/usr/local \
     && make \
     && make install

autoconf/ax_c_float_words_bigendian.diff

@@ -0,0 +1,92 @@
+diff --git a/m4/ax_c_float_words_bigendian.m4 b/m4/ax_c_float_words_bigendian.m4
+index 216b90d8..52036844 100644
+--- a/m4/ax_c_float_words_bigendian.m4
++++ b/m4/ax_c_float_words_bigendian.m4
+@@ -27,32 +27,81 @@
+ #   If neither value is found, the user is instructed to specify the
+ #   ordering.
+ #
++#   Early versions of this macro (i.e., before serial 12) would not work
++#   when interprocedural optimization (via link-time optimization) was
++#   enabled. This would happen when, say, the GCC/clang "-flto" flag, or the
++#   ICC "-ipo" flag was used, for example. The problem was that under
++#   these conditions, the compiler did not allocate for and write the special
++#   float value in the data segment of the object file, since doing so might
++#   not prove optimal once more context was available. Thus, the special value
++#   (in platform-dependent binary form) could not be found in the object file,
++#   and the macro would fail.
++#
++#   The solution to the above problem was to:
++#
++#     1) Compile and link a whole test program rather than just compile an
++#        object file. This ensures that we reach the point where even an
++#        interprocedural optimizing compiler writes values to the data segment.
++#
++#     2) Add code that requires the compiler to write the special value to
++#        the data segment, as opposed to "optimizing away" the variable's
++#        allocation. This could be done via compiler keywords or options, but
++#        it's tricky to make this work for all versions of all compilers with
++#        all optimization settings. The chosen solution was to make the exit
++#        code of the test program depend on the storing of the special value
++#        in memory (in the data segment). Because the exit code can be
++#        verified, any compiler that aspires to be correct will produce a
++#        program binary that contains the value, which the macro can then find.
++#
++#   How does the exit code depend on the special value residing in memory?
++#   Memory, unlike variables and registers, can be addressed indirectly at run
++#   time. The exit code of this test program is a result of indirectly reading
++#   and writing to the memory region where the special value is supposed to
++#   reside. The actual memory addresses used and the values to be written are
++#   derived from the the program input ("argv") and are therefore not known at
++#   compile or link time. The compiler has no choice but to defer the
++#   computation to run time, and to prepare by allocating and populating the
++#   data segment with the special value. For further details, refer to the
++#   source code of the test program.
++#
++#   Note that the test program is never meant to be run. It only exists to host
++#   a double float value in a given platform's binary format. Thus, error
++#   handling is not included.
++#
+ # LICENSE
+ #
+-#   Copyright (c) 2008 Daniel Amelang <dan@amelang.net>
++#   Copyright (c) 2008, 2023 Daniel Amelang <dan@amelang.net>
+ #
+ #   Copying and distribution of this file, with or without modification, are
+ #   permitted in any medium without royalty provided the copyright notice
+ #   and this notice are preserved. This file is offered as-is, without any
+ #   warranty.
+
+-#serial 11
++#serial 12
+
+ AC_DEFUN([AX_C_FLOAT_WORDS_BIGENDIAN],
+   [AC_CACHE_CHECK(whether float word ordering is bigendian,
+                   ax_cv_c_float_words_bigendian, [
+
+ ax_cv_c_float_words_bigendian=unknown
+-AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
++AC_LINK_IFELSE([AC_LANG_SOURCE([[
++
++#include <stdlib.h>
++
++static double m[] = {9.090423496703681e+223, 0.0};
+
+-double d = 90904234967036810337470478905505011476211692735615632014797120844053488865816695273723469097858056257517020191247487429516932130503560650002327564517570778480236724525140520121371739201496540132640109977779420565776568942592.0;
++int main (int argc, char *argv[])
++{
++    m[atoi (argv[1])] += atof (argv[2]);
++    return m[atoi (argv[3])] > 0.0;
++}
+
+ ]])], [
+
+-if grep noonsees conftest.$ac_objext >/dev/null ; then
++if grep noonsees conftest$EXEEXT >/dev/null ; then
+   ax_cv_c_float_words_bigendian=yes
+ fi
+-if grep seesnoon conftest.$ac_objext >/dev/null ; then
++if grep seesnoon conftest$EXEEXT >/dev/null ; then
+   if test "$ax_cv_c_float_words_bigendian" = unknown; then
+     ax_cv_c_float_words_bigendian=no
+   else