Build failure on p5-Scalar-List-Utils (needed by Monit) on brand new Solaris 10 / pkgsrc install

[Stephen Nelson-Smith <stephen%atalanta-systems.com@localhost>]

I'm  trying to install monit on a freshly installed Solaris 10u11
machine, with a freshly bootstrapped pkgsrc.

My path is:

/usr/sbin:/usr/bin:/usr/pkg/bin:/usr/sfw/bin:/usr/xpg4/bin:/usr/ccs/bin

And my mk.conf is:

# Example /usr/pkg/etc/mk.conf file produced by bootstrap-pkgsrc
# Saturday, 17 September 2016 16:03:24 BST

.ifdef BSD_PKG_MK       # begin pkgsrc settings

ABI=                    32
PKGSRC_COMPILER=        gcc
GCCBASE=                /usr/sfw/bin/gcc
USE_NATIVE_GCC=         yes
PKG_DBDIR=              /var/db/pkg
LOCALBASE=              /usr/pkg
VARBASE=                /var
PKG_TOOLS_BIN=          /usr/pkg/sbin
PKGINFODIR=             info
PKGMANDIR=              man
ACCEPTABLE_LICENSES+= gnu-agpl-v3

TOOLS_PLATFORM.install?=        /usr/pkg/bin/bsdinstall
TOOLS_PLATFORM.awk?=            /usr/pkg/bin/nawk
TOOLS_PLATFORM.sed?=            /usr/pkg/bin/nbsed
TOOLS_PLATFORM.sh?=             /usr/bin/bash
CFLAGS+=                -O2
DBG=                    # prevent DBG from adding default optimizer flags

.endif                  # end pkgsrc settings

The build blows up at usr/pkgsrc/devel/p5-Scalar-List-Utils

The start of the error looks like:

WARNING: No /var/db/pkg/pkg-vulnerabilities file found.
WARNING: To fix run: `/usr/pkg/sbin/pkg_admin -K /var/db/pkg
fetch-pkg-vulnerabilities'.
gcc: unrecognized option `-pthread'
In file included from
/usr/pkgsrc/devel/p5-Scalar-List-Utils/work/.buildlink/lib/perl5/5.24.0/i386-solaris-thread-multi/CORE/handy.h:77,
                 from
/usr/pkgsrc/devel/p5-Scalar-List-Utils/work/.buildlink/lib/perl5/5.24.0/i386-solaris-thread-multi/CORE/perl.h:2688,
                 from ListUtil.xs:7:
/usr/include/stdbool.h:42:2: #error "Use of <stdbool.h> is valid only
in a c99 compilation environment."
In file included from ListUtil.xs:7:
/usr/pkgsrc/devel/p5-Scalar-List-Utils/work/.buildlink/lib/perl5/5.24.0/i386-solaris-thread-multi/CORE/perl.h:3801:
error: syntax error before "bool"
/usr/pkgsrc/devel/p5-Scalar-List-Utils/work/.buildlink/lib/perl5/5.24.0/i386-solaris-thread-multi/CORE/perl.h:3801:
warning: no semicolon at end of struct or union
/usr/pkgsrc/devel/p5-Scalar-List-Utils/work/.buildlink/lib/perl5/5.24.0/i386-solaris-thread-multi/CORE/perl.h:3804:
error: syntax error before '}' token

Any pointers would be most welcome.

S.