ci: freebsd: install bzip2 (freetype2's pkgconfig Requires)

xfont2's pkg-config dependency lookup failed once the IGNORE_OSVERSION
fix (previous commit) let the package-version check through to the
actual build: freetype2's .pc file Requires: bzip2, but bzip2 wasn't in
the install list, so pkgconfig couldn't generate cflags for xfont2 and
meson bailed. Pre-existing gap, unmasked (not caused) by the previous
fix - this lane never got far enough to hit it before. The 'ld: error:
undefined symbol: main' lines in the same log are unrelated noise from
meson's own linker-capability probe (compiling a main-less test
program to detect LLD), not a real link failure.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

.github/scripts/freebsd/install-pkg.sh

@@ -39,6 +39,7 @@ retry pkg update -f
 
 echo "--> install extra dependencies"
 retry pkg install -y \
+    bzip2 \
     curl \
     git \
     libdrm \