https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66563
--- Comment #27 from John Paul Adrian Glaubitz <glaubitz at physik dot fu-berlin.de> --- Alright, I have tracked it down now! It's definitely a bug in mpfr4 and *not* gcc. I rebuilt both mpfr4_3.1.2-1 and mpfr4_3.1.2-3 with the latest compiler we have in Debian which is gcc-4.9_4.9.2-21 (r224436). This is the result with the compile test of wmfire with mpfr4_3.1.2-1: glaubitz@tirpitz:~/debian/segfault-test/wmfire-1.2.4/src$ gcc wmfire.c -o wmfire.o $(pkg-config --cflags gdk-2.0) $(pkg-config --cflags libgtop-2.0) wmfire.c: In function ‘do_help’: wmfire.c:770:62: error: ‘VERSION’ undeclared (first use in this function) fprintf(stderr, "\nWmfire - Flaming Monitor Dock V %s\n\n", VERSION); ^ wmfire.c:770:62: note: each undeclared identifier is reported only once for each function it appears in glaubitz@tirpitz:~/debian/segfault-test/wmfire-1.2.4/src$ This is the result with mpfr4_3.1.2-3: glaubitz@tirpitz:~/debian/segfault-test/wmfire-1.2.4/src$ gcc wmfire.c -o wmfire.o $(pkg-config --cflags gdk-2.0) $(pkg-config --cflags libgtop-2.0) wmfire.c: In function ‘draw_fire’: wmfire.c:559:6: internal compiler error: Segmentation fault psi = i * 3.14 / 20.0; ^ Please submit a full bug report, with preprocessed source if appropriate. See <file:///usr/share/doc/gcc-4.9/README.Bugs> for instructions. Preprocessed source stored into /tmp/cc4xNN4u.out file, please attach this to your bugreport. glaubitz@tirpitz:~/debian/segfault-test/wmfire-1.2.4/src Again, *both* compiled fresh with the *same* compiler. Adrian