p5.34-devel-mat-dumper fails to build on Leopard: error: ‘for’ loop initial declaration used outside C99 mode

[barracuda156]

Building Devel-MAT-Dumper
/usr/bin/gcc-4.2 -I/opt/local/lib/perl5/5.34/darwin-thread-multi-2level/CORE -DVERSION="0.46" -DXS_VERSION="0.46" -c -fno-common -DPERL_DARWIN -pipe -Os -fno-strict-aliasing -fstack-protector -I/opt/local/include -D_FORTIFY_SOURCE=2 -DPERL_USE_SAFE_PUTENV -Wno-error=implicit-function-declaration -O3 -o lib/Devel/MAT/Dumper.o lib/Devel/MAT/Dumper.c
lib/Devel/MAT/Dumper.xs: In function ‘writestruct’:
lib/Devel/MAT/Dumper.xs:1054: error: ‘for’ loop initial declaration used outside C99 mode
lib/Devel/MAT/Dumper.xs:1070: error: ‘for’ loop initial declaration used outside C99 mode
error building lib/Devel/MAT/Dumper.o from 'lib/Devel/MAT/Dumper.c' at /opt/local/lib/perl5/5.34/ExtUtils/CBuilder/Base.pm line 185.
Command failed:  cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_perl_p5-devel-mat-dumper/p5.34-devel-mat-dumper/work/Devel-MAT-Dumper-0.46" && /opt/local/bin/perl5.34 Build build 
Exit code: 2

Same error also on 10.6.