Using libfontenc from git, if zlib is not installed on the host system, the
configure script notices:

checking for gzclose in -lz... no

However, it continues.  The build certainly notices:

 gcc -DHAVE_CONFIG_H -I. -I. -I.. -I../include -DFONTENC_NO_LIBFONT
-DFONT_ENCODINGS_DIRECTORY=\"/usr/local/lib/X11/fonts/encodings/encodings.dir\"
-g -O2 -MT encparse.lo -MD -MP -MF .deps/encparse.Tpo -c encparse.c  -fPIC -DPIC
-o .libs/encparse.o
encparse.c:52:18: error: zlib.h: No such file or directory
encparse.c:53: error: expected '=', ',', ';', 'asm' or '__attribute__' before
'FontFilePtr'


The configure script should really bail out if zlib isn't present in the build
environment.