gmake setup failure on OpenBSD

mechanicum$ gnat build --version
GNAT 11.2.0
Copyright (C) 1996-2021, Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSEth GNAT:

when running gmake setup on OpenBSD in the aws-22.0.0 directory

I get the following output

mechanicum$ gmake setup
gmake[1]: Entering directory '/usr/local/src/Ada/aws-22.0.0/config'
gprbuild: "xoscons" up to date
Setup OS specific definitions
aws-os_lib-tmplt.c: In function 'main':
aws-os_lib-tmplt.c:324:122: error: 'uintptr_t' undeclared (first use in this function)
324 | /NOGEN/ CND(SIN_FAMILY_OFFSET, "sin_family offset in record");
| ^
aws-os_lib-tmplt.c:183:1: note: 'uintptr_t' is defined in header '<stdint.h>'; did you forget to '#include <stdint.h>'?
182 | # include <sys/time.h>
+++ |+#include <stdint.h>
183 | #endif
aws-os_lib-tmplt.c:324:122: note: each undeclared identifier is reported only once for each function it appears in
324 | /NOGEN/ CND(SIN_FAMILY_OFFSET, "sin_family offset in record");
| ^
raised raised ADA.IO_EXCEPTIONS.NAME_ERROR : aws-os_lib-tmplt.s: No such file or directory

gmake[1]: *** [Makefile:90: ../.build/x86_64-unknown-openbsd7.0/debug/../setup/src/aws-os_lib.ads] Error 1
gmake[1]: Leaving directory '/usr/local/src/Ada/aws-22.0.0/config'
gmake: *** [Makefile:162: config_setup] Error 2

Start by reproducing gmake setup in the config directory on OpenBSD and inspect aws-os_lib-tmplt.c around line 183, along with the setup rule referenced by Makefile:90. Done means the C setup step completes without the uintptr_t error and generates aws-os_lib.ads successfully.