unix: Fix zerrors generation on illumos

zerrors generated on illumos seems to be different from those generated
on solaris. This commit updates mkerrors.sh to handle those platform
differences.

Author: Araragi Hokuto

unix/mkall.sh

@@ -192,7 +192,7 @@ solaris_amd64)
 	;;
 illumos_amd64)
         mksyscall="go run mksyscall_solaris.go"
-	mkerrors=
+	mkerrors="$mkerrors -m64"
 	mksysnum=
 	mktypes=
 	;;

unix/mkerrors.sh

@@ -23,17 +23,24 @@ if [[ "$GOOS" = "linux" ]] && [[ "$GOLANG_SYS_BUILD" != "docker" ]]; then
 	exit 1
 fi
 
-if [[ "$GOOS" = "aix" ]]; then
+if [[ "$GOOS" = "aix" ]] || [[ "$GOOS" = "illumos" ]]; then
 	CC=${CC:-gcc}
 else
 	CC=${CC:-cc}
 fi
 
-if [[ "$GOOS" = "solaris" ]]; then
+if [[ "$GOOS" = "solaris" ]] || [[ "$GOOS" = "illumos" ]]; then
 	# Assumes GNU versions of utilities in PATH.
 	export PATH=/usr/gnu/bin:$PATH
 fi
 
+buildtags="${GOARCH},${GOOS}"
+
+# Solaris zerrors should not be compiled on illumos
+if [[ "$GOOS" = "solaris" ]]; then
+        buildtags="$buildtags,!illumos"
+fi
+
 uname=$(uname)
 
 includes_AIX='
@@ -580,7 +587,7 @@ echo '#include <signal.h>' | $CC -x c - -E -dM $ccflags |
 echo '// mkerrors.sh' "$@"
 echo '// Code generated by the command above; see README.md. DO NOT EDIT.'
 echo
-echo "// +build ${GOARCH},${GOOS}"
+echo "// +build $buildtags"
 echo
 go tool cgo -godefs -- "$@" _const.go >_error.out
 cat _error.out | grep -vf _error.grep | grep -vf _signal.grep