gegl: semi-fix for x-compile

cross-compilation is basically broken:
../../bin/gegl: line 117: gegl-0.2.0/bin/.libs/lt-gegl:
cannot execute binary file

however this change makes it at least working for x86_64->i386 cross-
compilation (assuming the user's kernel supports IA32 emulation and
he has /lib/ld-musl-i386.so.1 set up).
gperf: fix for x-compile
gsl: fix x-compile
groff: fix x-compile
icu: prepare for x-compile

icu cannot be cross-compiled currently.
it wants to get a path set to an icu source dir that was compiled for the
host architecture.
so we'd have to build it twice for host and target.

configure: error: Error!
Cross compiling but no --with-cross-build option specified -
please supply the path to an executable ICU's build root
gnumeric: fix x-compile
lcms2: fix x-compile
libtool.cross: add support for C++
poppler: fix x-compile
ijs: fix x-compile
imlib2: fix for x-compile
gstreamer01: fix x-compile
jansson: fix x-compile
jbig2dec: fix x-compile
json-c: fix x-compile
jupp: fix x-compile
kmod: fix x-compile
libIDL: fix x-compile
libcue: fix x-compile
libdwarf: fix lib part for x-compile