install: reenable matchpathcon-related code

The underlying performance problem is being dealt with in Automake
by limiting the number of install invocations, and in SELinux with
incremental changes as well as a potential new implementation.
* src/Makefile.am (ginstall_CPPFLAGS) [ENABLE_MATCHPATHCON]: Define.
* src/install.c [ENABLE_WHEN_MATCHPATHCON_IS_MORE_EFFICIENT]:
Rename to ENABLE_MATCHPATHCON.
* NEWS: mention this change

NEWS

@@ -25,6 +25,11 @@ GNU coreutils NEWS                                    -*- outline -*-
   tac: avoid segfault with --regex (-r) and multiple files, e.g.,
   "echo > x; tac -r x x".  [bug present at least in textutils-1.8b, from 1992]
 
+** Changes in behavior
+
+  install once again sets SELinux context, when possible
+  [it was deliberately disabled in 6.9.90]
+
 
 * Noteworthy changes in release 6.11 (2008-04-19) [stable]
 

src/Makefile.am

@@ -256,6 +256,8 @@ sha384sum_CPPFLAGS = -DHASH_ALGO_SHA384=1 $(AM_CPPFLAGS)
 sha512sum_SOURCES = md5sum.c
 sha512sum_CPPFLAGS = -DHASH_ALGO_SHA512=1 $(AM_CPPFLAGS)
 
+ginstall_CPPFLAGS = -DENABLE_MATCHPATHCON=1 $(AM_CPPFLAGS)
+
 editpl = sed -e 's,@''PERL''@,$(PERL),g'
 
 BUILT_SOURCES += dircolors.h

src/install.c

@@ -199,7 +199,7 @@ cp_option_init (struct cp_options *x)
   x->src_info = NULL;
 }
 
-#ifdef ENABLE_WHEN_MATCHPATHCON_IS_MORE_EFFICIENT
+#ifdef ENABLE_MATCHPATHCON
 /* Modify file context to match the specified policy.
    If an error occurs the file will remain with the default directory
    context.  */