Document that --enable-static-pie implies PIE

To build static PIE, all .o files are compiled with -fPIE.  Since
--enable-static-pie is designed to provide additional security hardening
benefits, it also implies that glibc programs and tests are created as
dynamic position independent executables (PIE) by default for better
security hardening.

Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>

	* manual/install.texi: Document that --enable-static-pie
	implies PIE.
	* INSTALL: Regenerated.

ChangeLog

@@ -1,3 +1,9 @@
+2017-12-19  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* manual/install.texi: Document that --enable-static-pie
+	implies PIE.
+	* INSTALL: Regenerated.
+
 2017-12-19  Bernd Edlinger  <bernd.edlinger@hotmail.de>
 
 	[BZ #21309]

INSTALL

@@ -93,7 +93,9 @@ will be used, and CFLAGS sets optimization options for the compiler.
      programs as well as static tests are built as static PIE, except
      for those marked with no-pie.  The resulting glibc can be used with
      the GCC option, -static-pie, which is available with GCC 8 or
-     above, to create static PIE.
+     above, to create static PIE. This option also implies that glibc
+     programs and tests are created as dynamic position independent
+     executables (PIE) by default.
 
 '--disable-profile'
      Don't build libraries with profiling information.  You may want to

manual/install.texi

@@ -123,7 +123,8 @@ address without help from a dynamic linker.  All static programs as
 well as static tests are built as static PIE, except for those marked
 with no-pie.  The resulting glibc can be used with the GCC option,
 -static-pie, which is available with GCC 8 or above, to create static
-PIE.
+PIE.  This option also implies that glibc programs and tests are created
+as dynamic position independent executables (PIE) by default.
 
 @item --disable-profile
 Don't build libraries with profiling information.  You may want to use