refactor autoconf png and jpeg checks

Makefile.in

@@ -98,12 +98,6 @@ GIF_INC= @GIF_INC@
 GIF_LIB= @GIF_LIB@
 GIF=	 @GIF_ENABLED@
 
-# 
-# ZLIB option (compressed SVG)
-#
-ZLIB_INC=  @ZLIB_INC@
-ZLIB_LIB=  @ZLIB_LIB@
-ZLIB=      @ZLIB_ENABLED@
 
 # JPEG distribution (raster support for grayscale JPEG images, INPUT ONLY).
 JPEG_INC= @JPEG_INC@
@@ -257,7 +251,7 @@ INCLUDES = $(FT_INC) $(REGEX_INC) $(PNG_INC) $(GIF_INC) $(JPEG_INC) $(GD_INC) \
         $(AGG_INC) $(OGL_INC) $(FTGL_INC) $(PROJ_INC) $(EGIS_INC) \
         $(SDE_INC) $(GDAL_INC) $(POSTGIS_INC) $(MYSQL_INC) \
         $(CURL_INC) $(ORACLESPATIAL_INC) $(GEOS_INC) $(ICONV_INC) \
-        $(FASTCGI_INC) $(EXEMPI_INC) $(ZLIB_INC) $(XML2_INC) $(FRIBIDI_INC) $(CAIRO_INC) $(LIBSVG_CAIRO_INC) \
+        $(FASTCGI_INC) $(EXEMPI_INC) $(XML2_INC) $(FRIBIDI_INC) $(CAIRO_INC) $(LIBSVG_CAIRO_INC) \
 		  $(APR_INC) $(APACHE_INC)
 
 FLAGS = @DEBUG_FLAGS@ $(DEFINES) $(INCLUDES)
@@ -270,7 +264,7 @@ SUP_LIBS =  $(FT_LIB) $(GD_LIB) $(OGL_LIB) $(FTGL_LIB) $(PROJ_LIBS) \
           $(JPEG_LIB) $(PNG_LIB) $(GIF_LIB) $(SDE_LIB) $(GDAL_LIB) $(POSTGIS_LIB) \
 	  $(MYSQL_LIB) $(CURL_LIB) $(ORACLESPATIAL_LIB) $(GEOS_LIB) \
 	  $(THREAD_LIB) $(ICONV_LIB) $(FASTCGI_LIB) $(EXEMPI_LIB) $(XSLT_LIB) $(EXSLT_LIB) \
-	  $(ZLIB_LIB) $(XML2_LIB) $(FRIBIDI_LIB) $(XTRALIBS)  $(CAIRO_LIB) $(LIBSVG_CAIRO_LIB) \
+	  $(XML2_LIB) $(FRIBIDI_LIB) $(XTRALIBS)  $(CAIRO_LIB) $(LIBSVG_CAIRO_LIB) \
 	  $(APR_LIB)
 
 # STATIC_LIBS is full filename with path of libs that will be statically linked