[plt-scheme] mz-372 does not allow -O3 optimization

hi

I tried to compile mz-372 with -O3 optimization but failed,

Copying /build/mz-372/collects/mzlib/private/cm-ctime.ss to /build/
mz-372/src/mzscheme/gc2/xform-collects/mzlib/private/cm-ctime.ss
Compiling xform support...
Done making xform-collects.
make[4]: *** [xsrc/precomp.h] Segmentation fault
make[4]: Leaving directory `/build/mz-372/src/mzscheme/gc2'
make[3]: *** [all] Error 2
make[3]: Leaving directory `/build/mz-372/src/mzscheme/gc2'
make[2]: *** [3m] Error 2
make[2]: Leaving directory `/build/mz-372/src/mzscheme'
make[1]: *** [3m] Error 2
make[1]: Leaving directory `/build/mz-372/src'
make: *** [all] Error 2

-O2 works OK.
I don't really need any optimization, just reporting this problem.