gcc8 on CentOS 7

[Jason Bacon <outpaddling%yahoo.com@localhost>]

I've been doing pbulk builds with gcc6 as a minimum for a while and this 
has been running smoothly.

I have a full build running with gcc7 now and that appears to be working 
well also.

However, with gcc8 I'm hitting an  error:

make[3]: Entering directory 
`/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build/gcc'
/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build/./prev-gcc/xg++ 
-B/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build/./prev-gcc/ 
-B/home/bacon/Pkgsrc/pkg/gcc8/x86_64-redhat-linux/bin/ -nostdinc++ 
-B/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build/prev-x86_64-redhat-linux/libstdc++-v3/src/.libs 
-B/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build/prev-x86_64-redhat-linux/libstdc++-v3/libsupc++/.libs 
-I/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build/prev-x86_64-redhat-linux/libstdc++-v3/include/x86_64-redhat-linux 
-I/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build/prev-x86_64-redhat-linux/libstdc++-v3/include 
-I/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/gcc-8.2.0/libstdc++-v3/libsupc++ 
-L/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build/prev-x86_64-redhat-linux/libstdc++-v3/src/.libs 
-L/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build/prev-x86_64-redhat-linux/libstdc++-v3/libsupc++/.libs 
-no-pie   -g -O2 -gtoggle -DIN_GCC     -fno-exceptions -fno-rtti 
-fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings 
-Wcast-qual -Wmissing-format-attribute -Woverloaded-virtual -pedantic 
-Wno-long-long -Wno-variadic-macros -Wno-overlength-strings   
-DHAVE_CONFIG_H -static-libstdc++ -static-libgcc 
-Wl,-R/home/bacon/Pkgsrc/pkg/lib   -o cc1 c/c-lang.o 
c-family/stub-objc.o attribs.o c/c-errors.o c/c-decl.o c/c-typeck.o 
c/c-convert.o c/c-aux-info.o c/c-objc-common.o c/c-parser.o c/c-fold.o 
c/gimple-parser.o c-family/c-common.o c-family/c-cppbuiltin.o 
c-family/c-dump.o c-family/c-format.o c-family/c-gimplify.o 
c-family/c-indentation.o c-family/c-lex.o c-family/c-omp.o 
c-family/c-opts.o c-family/c-pch.o c-family/c-ppoutput.o 
c-family/c-pragma.o c-family/c-pretty-print.o c-family/c-semantics.o 
c-family/c-ada-spec.o c-family/c-ubsan.o c-family/known-headers.o 
c-family/c-attribs.o c-family/c-warn.o c-family/c-spellcheck.o i386-c.o 
glibc-c.o \
  cc1-checksum.o libbackend.a main.o libcommon-target.a libcommon.a 
../libcpp/libcpp.a ../libdecnumber/libdecnumber.a libcommon.a 
../libcpp/libcpp.a   ../libbacktrace/.libs/libbacktrace.a 
../libiberty/libiberty.a ../libdecnumber/libdecnumber.a 
-L/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build/./isl/.libs  -lisl 
-L/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build/./gmp/.libs 
-L/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build/./mpfr/src/.libs 
-L/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build/./mpc/src/.libs -lmpc 
-lmpfr -lgmp -rdynamic -ldl  -lz
/home/bacon/Pkgsrc/pkg/bin/gld: cannot find -lz
collect2: error: ld returned 1 exit status
make[3]: *** [cc1] Error 1
make[3]: Leaving directory 
`/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build/gcc'
make[2]: *** [all-stage2-gcc] Error 2
make[2]: Leaving directory `/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build'
make[1]: *** [stage2-bubble] Error 2
make[1]: Leaving directory `/home/bacon/Pkgsrc/pkgsrc/lang/gcc8/work/build'
make: *** [all] Error 2
*** Error code 2

Stop.
bmake.bin[1]: stopped in /home/bacon/Pkgsrc/pkgsrc/lang/gcc8
*** Error code 1

Stop.
bmake.bin: stopped in /home/bacon/Pkgsrc/pkgsrc/lang/gcc8

zlib is a dependency and it is installed:

Linux centosdev.ceas  bacon ~/Pkgsrc/pkgsrc/lang/gcc8 1009: ls 
~/Pkgsrc/pkg/lib/libz*
/home/bacon/Pkgsrc/pkg/lib/libz.a /home/bacon/Pkgsrc/pkg/lib/libz.so.1@
/home/bacon/Pkgsrc/pkg/lib/libz.la* 
/home/bacon/Pkgsrc/pkg/lib/libz.so.1.0.2*
/home/bacon/Pkgsrc/pkg/lib/libz.so@

Linux centosdev.ceas  bacon ~/Pkgsrc/pkgsrc/lang/gcc8 1010: grep zlib 
Makefile
CONFIGURE_ARGS+=    --with-system-zlib
.include "../../devel/zlib/buildlink3.mk"

Any ideas why the build system is not locating it?

Thanks,

    JB