Makefile, specs: Honour %{_sbindir} for helper tools

Fedora 42 maps %{_sbindir} to /usr/bin. Export SBINDIR=%{_sbindir} in
the spec files and let the iscsi-scst/scstadmin Makefiles honour that
variable.

Fixes "File not found: .../iscsi-scst-adm" on unified-/usr systems while
keeping older distros unchanged.

iscsi-scst/Makefile

@@ -12,7 +12,7 @@ endif
 SHELL=/bin/bash
 
 SCST_DIR := $(shell echo "$$PWD")/../scst/src
-SBINDIR := $(PREFIX)/sbin
+SBINDIR ?= $(PREFIX)/sbin
 INITDIR := /etc/init.d
 RCDIR := /etc/rc.d
 MANDIR ?= $(PREFIX)/man

scst-dkms.spec.in

@@ -148,7 +148,7 @@ for d in scst fcst iscsi-scst qla2x00t-32gbit/qla2x00-target scst_local srpt; do
 done
 
 %install
-export KVER=%{kversion} PREFIX=%{_prefix} MANDIR=%{_mandir} DEPMOD=true
+export KVER=%{kversion} PREFIX=%{_prefix} MANDIR=%{_mandir} SBINDIR=%{_sbindir} DEPMOD=true
 export BUILD_2X_MODULE=y CONFIG_SCSI_QLA_FC=y CONFIG_SCSI_QLA2XXX_TARGET=y
 for d in scst; do
     DESTDIR=%{buildroot} %{make} -C $d install

scst.spec.in

@@ -142,7 +142,7 @@ done
 %install
 %{?kdir:export KDIR=%{kdir}}
 %{!?kdir:%{?kversion:export KVER=%{kversion}}}
-export PREFIX=%{_prefix} MANDIR=%{_mandir} DEPMOD=true
+export PREFIX=%{_prefix} MANDIR=%{_mandir} SBINDIR=%{_sbindir} DEPMOD=true
 export BUILD_2X_MODULE=y CONFIG_SCSI_QLA_FC=y CONFIG_SCSI_QLA2XXX_TARGET=y
 for d in scst; do
     DESTDIR=%{buildroot} %{make} -C $d install

scstadmin/scstadmin.spec.in

@@ -56,7 +56,7 @@ export PREFIX=%{_prefix} DESTDIR=%{buildroot} MANDIR=%{buildroot}%{_mandir}
 %{make}
 
 %install
-export PREFIX=%{_prefix} DESTDIR=%{buildroot} MANDIR=%{buildroot}%{_mandir}
+export PREFIX=%{_prefix} DESTDIR=%{buildroot} MANDIR=%{buildroot}%{_mandir} SBINDIR=%{_sbindir}
 %{make} install_vendor
 %scstadmin_perl_process_packlist
 rm -rf %{buildroot}/var/adm/perl-modules/scst

scstadmin/scstadmin.sysfs/Makefile

@@ -5,7 +5,7 @@ endif
 MODULE_VERSION = 1.0.0
 TOOL = scstadmin
 
-SBINDIR := $(PREFIX)/sbin
+SBINDIR ?= $(PREFIX)/sbin
 
 all: perl-module