Fix the following autobuild error on configs with host GCC15.
```
/workdir/instance-0/output-1/host/bin/ccache /usr/bin/gcc -O2 -DNDEBUG -Wall -Wstrict-prototypes -Wundef -Wmissing-declarations -Wmissing-prototypes -Wwrite-strings -fno-strict-aliasing -Werror=declaration-after-statement -fno-builtin -fno-common -Werror=return-type -Wno-unused-local-typedefs -DHAVE_STDINT_H=1 -DHAVE_DIRENT_H=1 -DHAVE_SYS_DIR_H=1 -DHAVE_SYS_TIME_H=1 -DHAVE_SYS_TIMES_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_LIBDL=1 -DGX_COLOR_INDEX_TYPE="unsigned long long" -D__USE_UNIX98=1 -DHAVE_SNPRINTF -O2 -I/workdir/instance-0/output-1/host/include -L/workdir/instance-0/output-1/host/lib -Wl,-rpath,/workdir/instance-0/output-1/host/lib -DNOCONTRIB -DHAVE_RESTRICT=1 -DHAVE_LIMITS_H=1 -DHAVE_STRING_H=1 -fno-strict-aliasing -O2 -I/workdir/instance-0/output-1/host/include -L/workdir/instance-0/output-1/host/lib -Wl,-rpath,/workdir/instance-0/output-1/host/lib -DHAVE_POPEN_PROTO=1 -I./base -o ./obj/aux/genconf ./base/genconf.c -lz
In file included from ./base/genconf.c:18:
./base/stdpre.h:348:13: error: 'bool' cannot be defined via 'typedef'
348 | typedef int bool;
| ^~~~
./base/stdpre.h:348:13: note: 'bool' is a keyword with '-std=c23' onwards
./base/stdpre.h:348:1: warning: useless type name in empty declaration
348 | typedef int bool;
| ^~~~~~~
```
This is due to the change in the default C language version in GCC15.
The patch included is not exactly the same as the upstream one, it only
picks the part that fix the `bool` definition and dropped the declaration
type changes.
Fixes: https://autobuild.buildroot.org/results/9c6/9c6cbff256635c6ab4be4c5b7bf18f9d3c4b46681
Signed-off-by: Thomas Perale <thomas.perale@mind.be>
Signed-off-by: Julien Olivain <ju.o@free.fr>
fa45c47fcb