So, I added --enable-svg and --enable-canvas to my Mozilla Firefox build config the other day. Apparently that forces me into building Cairo, which, um, doesn't build.
m:\source-HEAD\mozilla\gfx\cairo\cairo\src\cairo-win32-private.h(43) : warning C4005: 'WINVER' : macro redefinition
command-line arguments : see previous definition of 'WINVER'
../../../../../../source-HEAD\mozilla\gfx\cairo\cairo\src\cairo-win32.h(66) : fatal error C1189: #error : Cairo was not compiled with support for the win32 backend
make[4]: Leaving directory `/cygdrive/m/tree-firefox-debug/objdir/gfx/cairo/cairo/src'
make[3]: Leaving directory `/cygdrive/m/tree-firefox-debug/objdir/gfx/cairo'
make[2]: Leaving directory `/cygdrive/m/tree-firefox-debug/objdir/gfx'
make[1]: Leaving directory `/cygdrive/m/tree-firefox-debug/objdir'
make: Leaving directory `/cygdrive/m/tree-firefox-debug/objdir'
Update: It seems that, on way or another, I ended up with cairo-features.h in the srcdir without it being listed in CVS\Entries, so it never got removed. Thanks to vlad who suggested looking for that file in other locations. Let's hope it builds now.