better to use GNU make and override also exec_prefix

emacs/emacs.spec

@@ -40,7 +40,7 @@ Source0:      ftp://ftp.gnu.org/gnu/emacs/emacs-%{version}.tar.gz
 #   build information
 Prefix:       %{l_prefix}
 BuildRoot:    %{l_buildroot}
-BuildPreReq:  OpenPKG, openpkg >= 0.9-20011025.0
+BuildPreReq:  OpenPKG, openpkg >= 0.9-20011025.0, make
 PreReq:       OpenPKG, openpkg >= 0.9-20011025.0
 AutoReq:      no
 AutoReqProv:  no
@@ -67,7 +67,9 @@ AutoReqProv:  no
 
 %install
     rm -rf $RPM_BUILD_ROOT
-    %{l_make} %{l_mflags} install prefix=$RPM_BUILD_ROOT%{l_prefix}
+    %{l_make} %{l_mflags} install \
+        prefix=$RPM_BUILD_ROOT%{l_prefix} \
+        exec_prefix=$RPM_BUILD_ROOT%{l_prefix}
     rm -f $RPM_BUILD_ROOT%{l_prefix}/info/dir
     rm -f $RPM_BUILD_ROOT%{l_prefix}/bin/emacs-%{version}
     rm -f $RPM_BUILD_ROOT%{l_prefix}/bin/rcs-checkin