gforth and gcc 4.7

Trying to build gforth with gcc 4.7 fails currently. The forth engine is build but it fails its included tests. The problem is that every newline the forth engine writes is replaced with 0x00 as seen in following diff: 0000010: 6566 696e 6564 2047 4458 2020 594f 5520 efined GDX YOU 0000020: 5348 4f55 4c44 2053 4545 2054 4845 2053 SHOULD SEE THE S 0000030: 5441 4e44 4152 4420 4752 4150 4849 4320 TANDARD GRAPHIC -0000040: 4348 4152 4143 5445 5253 3a00 2021 2223 CHARACTERS:. !"# ^^ actual output +0000040: 4348 4152 4143 5445 5253 3a0a 2021 2223 CHARACTERS:. !"# ^^ expected output 0000050: 2425 2627 2829 2a2b 2c2d 2e2f 3031 3233 $%&'()*+,-./0123 Removing -O2 from the compiler commandline fixes it, but I have no idea why this happens. Does anyone have an idea how this can be solved? Adrian