buildtools buildlog with gcc and c++17

gistfile1.txt

with cxxFlags="-O2 -std=c++17" in build_cross_tools_gcc4

(...)
Configuring in ./libcody
configure: creating cache ./config.cache
checking build system type... x86_64-unknown-haiku_buildhost
checking host system type... x86_64-unknown-haiku_buildhost
checking maintainer-mode... 
checking whether the C++ compiler works... yes
checking for C++ compiler default output file name... a.out
checking for suffix of executables... 
checking whether we are cross compiling... no
checking for suffix of object files... o
checking whether we are using the GNU C++ compiler... yes
checking whether g++ accepts -g... yes
checking whether g++ is for C++11... no
configure: error: C++11 is required
Makefile:7800: recipe for target 'configure-libcody' failed
make[1]: *** [configure-libcody] Error 1
make[1]: Leaving directory '/RAMDisk/test/cross-tools-x86_64-build/gcc'
Makefile:958: recipe for target 'all' failed
make: *** [all] Error 2
ERROR: Building gcc failed.
/Ports/haiku/test> 

libcody's config.log:

This file contains any messages produced by compilers while
running configure, to aid debugging if configure makes a mistake.

It was created by codylib configure 0.0, which was
generated by GNU Autoconf 2.69.  Invocation command line was

  $ /Ports/buildtools/gcc/libcody/configure --srcdir=/Ports/buildtools/gcc/libcody --cache-file=./config.cache --with-system-zlib --prefix=/Ports/haiku/test/cross-tools-x86_64 --disable-nls --disable-shared --with-system-zlib --enable-lto --enable-frame-pointer --enable-__cxa-atexit --enable-threads=posix --with-default-libstdcxx-abi=gcc4-compatible --with-sysroot=/Ports/haiku/test/cross-tools-x86_64/sysroot --disable-maintainer-mode --disable-libgomp --disable-libatomic --enable-multilib --enable-languages=c,c++,lto --program-transform-name=s&^&x86_64-unknown-haiku-& --disable-option-checking --build=x86_64-unknown-haiku_buildhost --host=x86_64-unknown-haiku_buildhost --target=x86_64-unknown-haiku

## --------- ##
## Platform. ##
## --------- ##

hostname = Flatty
uname -m = x86_64
uname -r = 1
uname -s = Haiku
uname -v = hrev55064+1 Apr 28 2021 20:37:2

/usr/bin/uname -p = unknown
/bin/uname -X     = unknown

/bin/arch              = unknown
/usr/bin/arch -k       = unknown
/usr/convex/getsysinfo = unknown
/usr/bin/hostinfo      = unknown
/bin/machine           = unknown
/usr/bin/oslevel       = unknown
/bin/universe          = unknown

PATH: .
PATH: /boot/home/config/non-packaged/bin
PATH: /boot/home/config/bin
PATH: /boot/system/non-packaged/bin
PATH: /bin
PATH: /boot/system/apps
PATH: /boot/system/preferences
PATH: /boot/home/config/non-packaged/lib/ruby/gem/bin
PATH: /Ports/haiku/test/cross-tools-x86_64/bin


## ----------- ##
## Core tests. ##
## ----------- ##

configure:1747: creating cache ./config.cache
configure:1875: checking build system type
configure:1889: result: x86_64-unknown-haiku_buildhost
configure:1909: checking host system type
configure:1922: result: x86_64-unknown-haiku_buildhost
configure:1958: checking maintainer-mode
configure:1960: result: 
configure:2098: checking for C++ compiler version
configure:2107: g++ --version >&5
g++ (2019_05_24) 8.3.0
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

configure:2118: $? = 0
configure:2107: g++ -v >&5
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/boot/system/develop/tools/bin/../lib/gcc/x86_64-unknown-haiku/8.3.0/lto-wrapper
Target: x86_64-unknown-haiku
Configured with: /sources/gcc-8.3.0/configure --build=x86_64-unknown-haiku --prefix=/packages/gcc-8.3.0_2019_05_24-9/.self/develop/tools --libexecdir=/packages/gcc-8.3.0_2019_05_24-9/.self/develop/tools/lib --mandir=/packages/gcc-8.3.0_2019_05_24-9/.self/documentation/man --docdir=/packages/gcc-8.3.0_2019_05_24-9/.self/documentation/packages/gcc --enable-threads=posix --disable-nls --enable-shared --with-gnu-ld --with-gnu-as --enable-version-specific-runtime-libs --enable-languages=c,c++,fortran,objc --enable-lto --enable-frame-pointer --with-pkgversion=2019_05_24 --enable-__cxa-atexit --with-system-zlib --enable-checking=release --with-bug-url=http://dev.haiku-os.org/ --with-default-libstdcxx-abi=gcc4-compatible --enable-libssp --disable-multilib
Thread model: posix
gcc version 8.3.0 (2019_05_24) 
configure:2118: $? = 0
configure:2107: g++ -V >&5
g++: error: unrecognized command line option '-V'
g++: fatal error: no input files
compilation terminated.
configure:2118: $? = 1
configure:2107: g++ -qversion >&5
g++: error: unrecognized command line option '-qversion'; did you mean '--version'?
g++: fatal error: no input files
compilation terminated.
configure:2118: $? = 1
configure:2138: checking whether the C++ compiler works
configure:2160: g++ -O2 -std=c++17    conftest.cpp  >&5
configure:2164: $? = 0
configure:2212: result: yes
configure:2215: checking for C++ compiler default output file name
configure:2217: result: a.out
configure:2223: checking for suffix of executables
configure:2230: g++ -o conftest -O2 -std=c++17    conftest.cpp  >&5
configure:2234: $? = 0
configure:2256: result: 
configure:2278: checking whether we are cross compiling
configure:2286: g++ -o conftest -O2 -std=c++17    conftest.cpp  >&5
configure:2290: $? = 0
configure:2297: ./conftest
configure:2301: $? = 0
configure:2316: result: no
configure:2321: checking for suffix of object files
configure:2343: g++ -c -O2 -std=c++17  conftest.cpp >&5
configure:2347: $? = 0
configure:2368: result: o
configure:2372: checking whether we are using the GNU C++ compiler
configure:2391: g++ -c -O2 -std=c++17  conftest.cpp >&5
configure:2391: $? = 0
configure:2400: result: yes
configure:2409: checking whether g++ accepts -g
configure:2429: g++ -c -g  conftest.cpp >&5
configure:2429: $? = 0
configure:2470: result: yes
configure:2494: checking whether g++ is for C++11
configure:2511: g++ -c -O2 -std=c++17  conftest.cpp >&5
conftest.cpp:11:2: error: #error "C++11 is required"
 #error "C++11 is required"
  ^~~~~
configure:2511: $? = 1
configure: failed program was:
| /* confdefs.h */
| #define PACKAGE_NAME "codylib"
| #define PACKAGE_TARNAME "codylib"
| #define PACKAGE_VERSION "0.0"
| #define PACKAGE_STRING "codylib 0.0"
| #define PACKAGE_BUGREPORT "github.com/urnathan/libcody"
| #define PACKAGE_URL ""
| /* end confdefs.h.  */
| 
| #if __cplusplus != 201103
| #error "C++11 is required"
| #endif
| 
| int
| main ()
| {
| 
|   ;
|   return 0;
| }
configure:2532: g++ -std=c++11 -c -O2 -std=c++17  conftest.cpp >&5
conftest.cpp:11:2: error: #error "C++11 is required"
 #error "C++11 is required"
  ^~~~~
configure:2532: $? = 1
configure: failed program was:
| /* confdefs.h */
| #define PACKAGE_NAME "codylib"
| #define PACKAGE_TARNAME "codylib"
| #define PACKAGE_VERSION "0.0"
| #define PACKAGE_STRING "codylib 0.0"
| #define PACKAGE_BUGREPORT "github.com/urnathan/libcody"
| #define PACKAGE_URL ""
| /* end confdefs.h.  */
| 
| #if __cplusplus != 201103
| #error "C++11 is required"
| #endif
| 
| int
| main ()
| {
| 
|   ;
|   return 0;
| }
configure:2552: g++ -c -O2 -std=c++17  conftest.cpp >&5
conftest.cpp:11:2: error: #error "C++11 is required"
 #error "C++11 is required"
  ^~~~~
configure:2552: $? = 1
configure: failed program was:
| /* confdefs.h */
| #define PACKAGE_NAME "codylib"
| #define PACKAGE_TARNAME "codylib"
| #define PACKAGE_VERSION "0.0"
| #define PACKAGE_STRING "codylib 0.0"
| #define PACKAGE_BUGREPORT "github.com/urnathan/libcody"
| #define PACKAGE_URL ""
| /* end confdefs.h.  */
| 
| #if __cplusplus > 201103
| #error "C++11 is required"
| #endif
| 
| int
| main ()
| {
| 
|   ;
|   return 0;
| }
configure:2556: result: no
configure:2558: error: C++11 is required

## ---------------- ##
## Cache variables. ##
## ---------------- ##

ac_cv_build=x86_64-unknown-haiku_buildhost
ac_cv_cxx_compiler_gnu=yes
ac_cv_env_CCC_set=
ac_cv_env_CCC_value=
ac_cv_env_CPPFLAGS_set=
ac_cv_env_CPPFLAGS_value=
ac_cv_env_CXXFLAGS_set=set
ac_cv_env_CXXFLAGS_value='-O2 -std=c++17'
ac_cv_env_CXX_set=set
ac_cv_env_CXX_value=g++
ac_cv_env_LDFLAGS_set=set
ac_cv_env_LDFLAGS_value=' '
ac_cv_env_LIBS_set=
ac_cv_env_LIBS_value=
ac_cv_env_build_alias_set=set
ac_cv_env_build_alias_value=x86_64-unknown-haiku_buildhost
ac_cv_env_host_alias_set=set
ac_cv_env_host_alias_value=x86_64-unknown-haiku_buildhost
ac_cv_env_target_alias_set=set
ac_cv_env_target_alias_value=x86_64-unknown-haiku
ac_cv_host=x86_64-unknown-haiku_buildhost
ac_cv_objext=o
ac_cv_prog_cxx_g=yes

## ----------------- ##
## Output variables. ##
## ----------------- ##

AR='ar'
CPPFLAGS=''
CXX='g++'
CXXFLAGS='-O2 -std=c++17'
DEFS=''
ECHO_C=''
ECHO_N='-n'
ECHO_T=''
EXCEPTIONS=''
EXEEXT=''
LDFLAGS=' '
LIBOBJS=''
LIBS=''
LTLIBOBJS=''
MAINTAINER=''
OBJEXT='o'
PACKAGE_BUGREPORT='github.com/urnathan/libcody'
PACKAGE_NAME='codylib'
PACKAGE_STRING='codylib 0.0'
PACKAGE_TARNAME='codylib'
PACKAGE_URL=''
PACKAGE_VERSION='0.0'
PATH_SEPARATOR=':'
PICFLAG=''
RANLIB='ranlib'
SHELL='/bin/sh'
ac_ct_CXX=''
bindir='${exec_prefix}/bin'
build='x86_64-unknown-haiku_buildhost'
build_alias='x86_64-unknown-haiku_buildhost'
build_cpu='x86_64'
build_os='haiku_buildhost'
build_vendor='unknown'
configure_args=''
datadir='${datarootdir}'
datarootdir='${prefix}/share'
docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
dvidir='${docdir}'
exec_prefix='NONE'
host='x86_64-unknown-haiku_buildhost'
host_alias='x86_64-unknown-haiku_buildhost'
host_cpu='x86_64'
host_os='haiku_buildhost'
host_vendor='unknown'
htmldir='${docdir}'
includedir='${prefix}/include'
infodir='${datarootdir}/info'
libdir='${exec_prefix}/lib'
libexecdir='${exec_prefix}/libexec'
localedir='${datarootdir}/locale'
localstatedir='${prefix}/var'
mandir='${datarootdir}/man'
oldincludedir='/usr/include'
pdfdir='${docdir}'
prefix='/Ports/haiku/test/cross-tools-x86_64'
program_transform_name='s&^&x86_64-unknown-haiku-&'
psdir='${docdir}'
sbindir='${exec_prefix}/sbin'
sharedstatedir='${prefix}/com'
sysconfdir='${prefix}/etc'
target_alias='x86_64-unknown-haiku'

## ----------- ##
## confdefs.h. ##
## ----------- ##

/* confdefs.h */
#define PACKAGE_NAME "codylib"
#define PACKAGE_TARNAME "codylib"
#define PACKAGE_VERSION "0.0"
#define PACKAGE_STRING "codylib 0.0"
#define PACKAGE_BUGREPORT "github.com/urnathan/libcody"
#define PACKAGE_URL ""

configure: exit 1