[openwrt/openwrt] tools: gnulib: do not cache C standard option test results

[LEDE Commits]

nick pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/ba76da4fe9fc07e62c7d94d2fb4e123e6f0c56c8

commit ba76da4fe9fc07e62c7d94d2fb4e123e6f0c56c8
Author: Michael Pratt <mcpratt at pm.me>
AuthorDate: Sat Aug 2 04:12:17 2025 -0400

    tools: gnulib: do not cache C standard option test results
    
    After eliminating the possibility of automake having a bug
    by testing a revert to the recent updates to automake,
    the problems regarding autoreconf with some packages
    was bisected to the gnulib update instead, through aclocal macros.
    
    With the new module, std-gnu23, some packages are failing build
    due to both the host compiler and cross compiler being tested for
    availability of C23 standard features with the configure script.
    The results of one is being cached and used for the other,
    while the two compilers are different versions and may or may not
    both support C23 options and would otherwise have conflicting results.
    
    A similar patch may have to be done
    for the next release of Autoconf
    if upstream GNU does not accept this solution.
    
    Reported-by: Georgi Valkov <gvalkov at gmail.com>
    Signed-off-by: Michael Pratt <mcpratt at pm.me>
    Link: https://github.com/openwrt/openwrt/pull/19627
    Signed-off-by: Nick Hainke <vincent at systemli.org>
---
 tools/gnulib/patches/190-stdc-m4-no-cache.patch | 59 +++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/tools/gnulib/patches/190-stdc-m4-no-cache.patch b/tools/gnulib/patches/190-stdc-m4-no-cache.patch
new file mode 100644
index 0000000000..1505da8402
--- /dev/null
+++ b/tools/gnulib/patches/190-stdc-m4-no-cache.patch
@@ -0,0 +1,59 @@
+--- a/m4/std-gnu11.m4
++++ b/m4/std-gnu11.m4
+@@ -185,8 +185,7 @@ AC_LANG_POP(C++)dnl
+ # else ACTION-IF-UNAVAILABLE.
+ AC_DEFUN([_AC_C_STD_TRY],
+ [AC_MSG_CHECKING([for $CC option to enable ]m4_translit($1, [c], [C])[ features])
+-AC_CACHE_VAL(ac_cv_prog_cc_$1,
+-[ac_cv_prog_cc_$1=no
++ac_cv_prog_cc_$1=no
+ ac_save_CC=$CC
+ AC_LANG_CONFTEST([AC_LANG_PROGRAM([$2], [$3])])
+ for ac_arg in '' $4
+@@ -197,7 +196,6 @@ do
+ done
+ rm -f conftest.$ac_ext
+ CC=$ac_save_CC
+-])# AC_CACHE_VAL
+ ac_prog_cc_stdc_options=
+ case "x$ac_cv_prog_cc_$1" in
+   x)
+@@ -523,8 +521,7 @@ fi
+ AC_DEFUN([_AC_CXX_STD_TRY],
+ [AC_MSG_CHECKING([for $CXX option to enable ]m4_translit(m4_translit($1, [x], [+]), [a-z], [A-Z])[ features])
+ AC_LANG_PUSH(C++)dnl
+-AC_CACHE_VAL(ac_cv_prog_cxx_$1,
+-[ac_cv_prog_cxx_$1=no
++ac_cv_prog_cxx_$1=no
+ ac_save_CXX=$CXX
+ AC_LANG_CONFTEST([AC_LANG_PROGRAM([$2], [$3])])
+ for ac_arg in '' $4
+@@ -535,7 +532,6 @@ do
+ done
+ rm -f conftest.$ac_ext
+ CXX=$ac_save_CXX
+-])# AC_CACHE_VAL
+ ac_prog_cxx_stdcxx_options=
+ case "x$ac_cv_prog_cxx_$1" in
+   x)
+--- a/m4/std-gnu23.m4
++++ b/m4/std-gnu23.m4
+@@ -696,8 +696,7 @@ AC_DEFUN([_AC_PROG_CC_STDC_EDITION_TRY],
+ [AC_REQUIRE([_AC_C_C$1_TEST_PROGRAM])]dnl
+ [AS_IF([test x$ac_prog_cc_stdc = xno],
+ [AC_MSG_CHECKING([for $CC option to enable C$1 features])
+-AC_CACHE_VAL([ac_cv_prog_cc_c$1],
+-[ac_cv_prog_cc_c$1=no
++ac_cv_prog_cc_c$1=no
+ ac_save_CC=$CC
+ AC_LANG_CONFTEST([AC_LANG_DEFINES_PROVIDED][$][ac_c_conftest_c$1_program])
+ for ac_arg in '' m4_normalize(m4_defn([_AC_C_C$1_OPTIONS]))
+@@ -707,7 +706,7 @@ do
+   test "x$ac_cv_prog_cc_c$1" != "xno" && break
+ done
+ rm -f conftest.$ac_ext
+-CC=$ac_save_CC])
++CC=$ac_save_CC
+ AS_IF([test "x$ac_cv_prog_cc_c$1" = xno],
+   [AC_MSG_RESULT([unsupported])],
+   [AS_IF([test "x$ac_cv_prog_cc_c$1" = x],