I have no idea if this is just my problem, but I was having a problem where if I compiled anything with gtk, I’d get:
/usr/lib/libpangoxft-1.0.so: undefined reference to `pango_fc_font_get_raw_extents’
solution below!
edit your /usr/lib/pkgconfig/pangoxft.pc, and where it says “Requires” make it say “pango pangoft2” instead of just “pango.” That solved it for me.