Build issues

I'm trying to build libgd with local libz, libpng, and libjpeg, without 
freetype, fontconfig, threads, or iconv.

The first issue is that there appears to be no option for no threads or 
no iconv.

The next is that configure appears to ignore the paths for libz, libpng 
and libjpeg.

Invoking configure with:

LDFLAGS="-L/usr/build/interfaces/libpng-1.6.25 
-L/usr/build/interfaces/zlib-1.2.8 -L/usr/build/interfaces/jpeg-9b" \
CFLAGS="-I/usr/build/interfaces/libpng-1.6.25 
-I/usr/build/interfaces/zlib-1.2.8 -I/usr/build/interfaces/jpeg-9b -fPIC" \
./configure --with-png=/usr/build/interfaces/libpng-1.6.26 \
--with-jpeg=/usr/build/interfaces/jpeg-9b \
--with-zlib=/usr/build/interfaces/zlib-1.2.6 \
--with-png=/usr/build/interfaces/libpng-1.6.25 \
--without-xpm \
--without-freetype \
--without-fontconfig \
--disable-shared

Yields:

** Configuration summary for libgd 2.2.3:

    Support for Zlib:                 yes
    Support for PNG library:          no
    Support for JPEG library:         no
    Support for WebP library:         no
    Support for TIFF library:         no
    Support for Freetype 2.x library: no
    Support for Fontconfig library:   no
    Support for Xpm library:          no
    Support for liq library:          no
    Support for pthreads:             yes


When I go ahead and run make, the build dies with:

libtool: compile:  gcc -std=gnu99 -DHAVE_CONFIG_H -I. -Werror 
-I/usr/build/interfaces/libpng-1.6.25 -I/usr/build/interfaces/zlib-1.2.8 
-I/usr/build/interfaces/jpeg-9b -fPIC -fvisibility=hidden -Wall -MT 
gdft.lo -MD -MP -MF .deps/gdft.Tpo -c gdft.c -o gdft.o
cc1: warnings being treated as errors
entities.h:17: warning: 'entities' defined but not used
gdft.c:1635: warning: 'font_path' defined but not used
make[2]: *** [gdft.lo] Error 1
make[2]: Leaving directory `/usr/build/interfaces/libgd-2.2.3/src'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/usr/build/interfaces/libgd-2.2.3/src'
make: *** [all-recursive] Error 1

Any help will be greatly appreciated.