Source: http://sourceware.org/ml/libc-alpha/2008-03/msg00105.html
Status: Not applied upstream

After reconfiguring, the value of slibdir changes from ${exec_prefix}/lib32 or
${exec_prefix}/lib64 to ${exec_prefix}/lib.

This is because the code that sets libdir is only executed if libc_cv_slibdir
is unset (this is to provide an override mechanism for subtargets).  If the
value of libc_cv_slibdir is read from the config cache the value of libdir is
never adjusted.  Or:

  $ rm config.cache 
  $ ~/src/glibc/configure --host=mips64-unknown-linux-gnu --build=i686-linux --prefix=/usr --cache-file=config.cache &>/dev/null
  $ grep libdir config.make 
  libdir = ${exec_prefix}/lib32
  slibdir = /lib32
  $ ~/src/glibc/configure --host=mips64-unknown-linux-gnu --build=i686-linux --prefix=/usr --cache-file=config.cache &>/dev/null
  $ grep libdir config.make 
  libdir = ${exec_prefix}/lib
  slibdir = /lib32

With the current logic, either both libdir and slibdir should be cached or
neither.  This patch renames slibdir so that it is no longer cached.

The patch has been in our tree for a few weeks now and produced no regressions
with glibc testing (make check).

Please apply if OK.

Adam

	* config.make.in (libc_cv_slibdir): Rename to slibdir.
	* configure.in: Rename libc_cv_slibdir to slibdir.
	* sysdeps/unix/sysv/linux/configure.in: Likewise.
	* ports/sysdeps/unix/sysv/linux/mips/configure.in: Likewise
	* configure: Regenerate.
	* sysdeps/unix/sysv/linux/configure: Likewise.
	* ports/sysdeps/unix/sysv/linux/mips/configure: Likewise.

Index: libc/config.make.in
===================================================================
--- libc.orig/config.make.in	2010-08-25 00:26:33.000000000 -0700
+++ libc/config.make.in	2010-09-25 12:31:21.460933356 -0700
@@ -10,7 +10,7 @@
 exec_prefix = @exec_prefix@
 datadir = @datadir@
 libdir = @libdir@
-slibdir = @libc_cv_slibdir@
+slibdir = @slibdir@
 localedir = @libc_cv_localedir@
 sysconfdir = @libc_cv_sysconfdir@
 libexecdir = @libexecdir@
Index: libc/configure.in
===================================================================
--- libc.orig/configure.in	2010-08-25 00:26:33.000000000 -0700
+++ libc/configure.in	2010-09-25 12:31:21.484430729 -0700
@@ -2337,7 +2337,7 @@
 fi
 AC_SUBST(old_glibc_headers)
 
-AC_SUBST(libc_cv_slibdir)
+AC_SUBST(slibdir)
 AC_SUBST(libc_cv_localedir)
 AC_SUBST(libc_cv_sysconfdir)
 AC_SUBST(libc_cv_rootsbindir)
Index: libc/sysdeps/unix/sysv/linux/configure.in
===================================================================
--- libc.orig/sysdeps/unix/sysv/linux/configure.in	2010-08-25 00:25:11.000000000 -0700
+++ libc/sysdeps/unix/sysv/linux/configure.in	2010-09-25 12:31:21.500430612 -0700
@@ -147,12 +147,12 @@
 case "$prefix" in
 /usr | /usr/)
   # 64-bit libraries on bi-arch platforms go in /lib64 instead of /lib.
-  # Allow earlier configure scripts to handle libc_cv_slibdir, libdir,
+  # Allow earlier configure scripts to handle slibdir, libdir,
   # and libc_cv_localedir.
-  test -n "$libc_cv_slibdir" || \
+  test -n "$slibdir" || \
   case $machine in
   sparc/sparc64 | x86_64 | powerpc/powerpc64 | s390/s390-64)
-    libc_cv_slibdir="/lib64"
+    slibdir="/lib64"
     if test "$libdir" = '${exec_prefix}/lib'; then
       libdir='${exec_prefix}/lib64';
       # Locale data can be shared between 32bit and 64bit libraries
@@ -160,7 +160,7 @@
     fi
     ;;
   *)
-    libc_cv_slibdir="/lib"
+    slibdir="/lib"
     ;;
   esac
   # Allow the user to override the path with --sysconfdir
Index: libc/ports/sysdeps/unix/sysv/linux/mips/configure.in
===================================================================
--- libc.orig/ports/sysdeps/unix/sysv/linux/mips/configure.in	2010-08-25 00:24:01.000000000 -0700
+++ libc/ports/sysdeps/unix/sysv/linux/mips/configure.in	2010-09-25 12:31:21.500430612 -0700
@@ -80,12 +80,12 @@
 case "$prefix" in
 /usr | /usr/)
   # 64-bit libraries on bi-arch platforms go in /lib64 instead of /lib.
-  # Allow earlier configure scripts to handle libc_cv_slibdir, libdir,
+  # Allow earlier configure scripts to handle slibdir, libdir,
   # and libc_cv_localedir.
-  test -n "$libc_cv_slibdir" || \
+  test -n "$slibdir" || \
   case $machine in
   mips/mips64/n64/* )
-    libc_cv_slibdir="/lib64"
+    slibdir="/lib64"
     if test "$libdir" = '${exec_prefix}/lib'; then
       libdir='${exec_prefix}/lib64';
       # Locale data can be shared between 32bit and 64bit libraries
@@ -93,7 +93,7 @@
     fi
     ;;
   mips/mips64/n32/* )
-    libc_cv_slibdir="/lib32"
+    slibdir="/lib32"
     if test "$libdir" = '${exec_prefix}/lib'; then
       libdir='${exec_prefix}/lib32';
       # Locale data can be shared between 32bit and 64bit libraries
@@ -101,7 +101,7 @@
     fi
     ;;
   *)
-    libc_cv_slibdir="/lib"
+    slibdir="/lib"
     ;;
   esac
 esac