Use %gomkdir because it's available in RHEL 9

There's no need to do a build just for this.

Resolves: #2165742

toolbox.spec

@@ -79,27 +79,13 @@ The %{name}-tests package contains system tests for %{name}.
 
 %patch102 -p1
 
-# %%gomkdir is absent from RHEL 8.
-GOBUILDDIR="$(pwd)/_build"
-GOSOURCEDIR="$(pwd)"
-if [[ ! -e "$GOBUILDDIR/bin" ]] ; then
-  install -m 0755 -vd "$GOBUILDDIR/bin"
-fi
-if [[ ! -e "$GOBUILDDIR/src/%{goipath}" ]] ; then
-  install -m 0755 -vd "$(dirname $GOBUILDDIR/src/%{goipath})"
-  ln -fs "$GOSOURCEDIR" "$GOBUILDDIR/src/%{goipath}"
-fi
-cd "$GOBUILDDIR/src/%{goipath}"
+%gomkdir -s %{_builddir}/%{extractdir}/src %{?rhel:-k}
 
 
 %build
 export %{gomodulesmode}
-GOBUILDDIR="$(pwd)/_build"
-export GOPATH="$GOBUILDDIR:%{gopath}"
+export GOPATH=%{gobuilddir}:%{gopath}
 export CGO_CFLAGS="%{optflags} -D_GNU_SOURCE -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64"
-ln -s src/cmd cmd
-ln -s src/pkg pkg
-ln -s src/vendor vendor
 
 %meson \
     -Dmigration_path_for_coreos_toolbox=true \