I’m 99% sure that this issue is down to the problem fixed in https://github.com/gcc-mirror/gcc/commit/6725f186cb70d48338f69456864bf469a12ee5be <https://github.com/gcc-mirror/gcc/commit/6725f186cb70d48338f69456864bf469a12ee5be> - which is included in GCC 12.2 - so I’ll go build 12.2.0 & try again

> On 6 Nov 2022, at 19:27, Simon Wright via Gcc-help <gcc-help@gcc.gnu.org <mailto:gcc-help@gcc.gnu.org>> wrote:
> 
> The boot compiler is GCC 12.1.0.
> 
> Configuration fails because the C compiler can’t produce an executable. I don’t have the log, but the errors were like
> 
> configure:3943: gcc -c -g  conftest.c >&5
> <built-in>: error: unknown value '13.0.0' of '-mmacosx-version-min'
> 
> I tried setting CFLAGS and CXXFLAGS as here:
> 
> export CFLAGS=-mmacosx-version-min=12.0.0
> export CXXFLAGS=-mmacosx-version-min=12.0.0
> 
> $GCC_SRC/configure                                                      \
>  --prefix=$PREFIX                                                      \
>  --without-libiconv-prefix                                             \
>  --disable-libmudflap                                                  \
>  --disable-libstdcxx-pch                                               \
>  --disable-libsanitizer                                                \
>  --disable-libcc1                                                      \
>  --disable-libcilkrts                                                  \
>  --disable-multilib                                                    \
>  --disable-nls                                                         \
>  --enable-languages=c,c++,ada                                          \
>  --host=$BUILD                                                         \
>  --target=$BUILD                                                       \
>  --build=$BUILD                                                        \
>  --without-isl                                                         \
>  --with-build-sysroot="$(xcrun --show-sdk-path)"                       \
>  --with-sysroot=                                                       \
>  --with-specs="%{!sysroot=*:--sysroot=%:if-exists-else($XCODE $CLU)}"  \
>  --with-build-config=no                                                \
>  --enable-bootstrap                                                    \
>  CFLAGS=-mmacosx-version-min=12.0.0                                    \
>  CXXFLAGS=-mmacosx-version-min=12.0.0 
> 
> (having checked that this flag was needed to avoid the error in a standard-alone compilation) but the configure now failed in fixincludes/. It seems that sometimes the CFLAGS setting is used and sometimes it isn’t??? See lines 3674, 3744, 3800, 3857, 3905 below and then 3943
> 
> configure:3652: checking whether the C compiler works
> configure:3674: gcc -mmacosx-version-min=12.0.0   conftest.c  >&5
> configure:3678: $? = 0
> configure:3726: result: yes
> configure:3729: checking for C compiler default output file name
> configure:3731: result: a.out
> configure:3737: checking for suffix of executables
> configure:3744: gcc -o conftest -mmacosx-version-min=12.0.0   conftest.c  >&5
> configure:3748: $? = 0
> configure:3770: result: 
> configure:3792: checking whether we are cross compiling
> configure:3800: gcc -o conftest -mmacosx-version-min=12.0.0   conftest.c  >&5
> configure:3804: $? = 0
> configure:3811: ./conftest
> configure:3815: $? = 0
> configure:3830: result: no
> configure:3835: checking for suffix of object files
> configure:3857: gcc -c -mmacosx-version-min=12.0.0  conftest.c >&5
> configure:3861: $? = 0
> configure:3882: result: o
> configure:3886: checking whether we are using the GNU C compiler
> configure:3905: gcc -c -mmacosx-version-min=12.0.0  conftest.c >&5
> configure:3905: $? = 0
> configure:3914: result: yes
> configure:3923: checking whether gcc accepts -g
> configure:3943: gcc -c -g  conftest.c >&5
> <built-in>: error: unknown value '13.0.0' of '-mmacosx-version-min'
> configure:3943: $? = 1
> configure: failed program was:
> | /* confdefs.h */
> | #define PACKAGE_NAME "fixincludes"
> | #define PACKAGE_TARNAME "fixincludes"
> | #define PACKAGE_VERSION " "
> | #define PACKAGE_STRING "fixincludes  "
> | #define PACKAGE_BUGREPORT ""
> | #define PACKAGE_URL ""
> | /* end confdefs.h.  */
> | 
> | int
> | main ()
> | {
> | 
> |   ;
> |   return 0;
> | }
> 
>