missing zlib linkage

[iioflow]

the compile_linux_* scripts are missing the explicit link to zlib. they need "-lz" appended after "-mxml", otherwise all builds will fail with undefined references to gzopen etc.:

Compiling source in /var/tmp/portage/media-sound/paulstretch-2.2/work/paulstretch-2.2-2 ...
/var/tmp/portage/media-sound/paulstretch-2.2/temp/ccau9w4Y.o: In function XMLwrapper::dosavefile(char*, int, char*)': /var/tmp/portage/media-sound/paulstretch-2.2/work/paulstretch-2.2-2/XMLwrapper.cpp:196: undefined reference togzopen'
/var/tmp/portage/media-sound/paulstretch-2.2/work/paulstretch-2.2-2/XMLwrapper.cpp:198: undefined reference to gzputs' /var/tmp/portage/media-sound/paulstretch-2.2/work/paulstretch-2.2-2/XMLwrapper.cpp:199: undefined reference togzclose'
....and so on

also happens when running the compile_* scripts directly, not just when using gentoo's source package manager. after patching compile_*.sh to include "-lz" the package builds and runs as expected.