pkg/56488: Solaris 10 compile issues, stdbool.h requires c99

[pekdon%gmail.com@localhost]

>Number:         56488
>Category:       pkg
>Synopsis:       Solaris 10 compile issues, stdbool.h requires c99
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    pkg-manager
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Mon Nov 08 07:20:00 +0000 2021
>Originator:     Claes Nästén
>Release:        trunk 2021-11-01
>Organization:
>Environment:
SunOS u40 5.10 Generic_153154-01 i86pc i386 i86pc
>Description:
While building amongst other things, git, I've stumbled accross a set of packages that end up including stdbool.h which will error on Solaris 10 with an error like:

/usr/include/stdbool.h:42:2: #error "Use of <stdbool.h> is valid only in a c99 compilation environment."

The packages I've found so far:

devel/flex
devel/p5-gettext
net/p5-Socket6
net/p5-Net-LibIDN
security/p5-Net-SSLeay
security/p5-GSSAPI
www/libpsl

This was found using the shipped GCC-3.4.3, using GCC-7.5.0 it's not visible assuming it is using C99 by default.
>How-To-Repeat:
Build any of the above mentioned packages and it will error out with the error message:

/usr/include/stdbool.h:42:2: #error "Use of <stdbool.h> is valid only in a c99 compilation environment."
>Fix:
Add (or change c to c99)

USE_LANGUAGES=         c99

In the Makefiles of the above mentioned packages.