The XML representation of the illumos system calls is generated in ../build.sh

--- gdb-14.2/gdb/data-directory/Makefile.in.orig
+++ gdb-14.2/gdb/data-directory/Makefile.in
@@ -51,8 +51,10 @@
 GEN_SYSCALLS_FILES = \
 	aarch64-linux.xml \
 	amd64-linux.xml \
+	amd64-illumos.xml \
 	arm-linux.xml \
 	i386-linux.xml \
+	i386-illumos.xml \
 	mips-n32-linux.xml \
 	mips-n64-linux.xml \
 	mips-o32-linux.xml \