Clarify the use of autoconf variables to ensure forced-unwind and C-cleanup support in chapter 5's Glibc. Fixes #2543.

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@9163 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

1 files changed, 10 insertions, 6 deletions

diff --git a/chapter05/glibc.xml b/chapter05/glibc.xml
index e3a5b6ee8..862a09f5a 100644
--- a/chapter05/glibc.xml
+++ b/chapter05/glibc.xml
@@ -120,17 +120,21 @@ esac</userinput></screen>
       <varlistentry>
         <term><parameter>libc_cv_forced_unwind=yes</parameter></term>
         <listitem>
-          <para>The build requires support for forced unwind, but because it is
-          being cross compiled, it cannot auto detect it. Setting this variable
-          on the command line explicitly tells the
-          <command>configure</command> script that support is available.</para>
+          <para>The linker installed during
+          <xref linkend="ch-tools-binutils-pass1"/> was cross-compiled and as
+          such cannot be used until Glibc has been installed.  This means that
+          the configure test for force-unwind support will fail, as it relies on
+          a working linker.  The libc_cv_forced_unwind=yes variable is passed in
+          order to inform <command>configure</command> that force-unwind
+          support is available without it having to run the test.</para>
         </listitem>
       </varlistentry>
       <varlistentry>
         <term><parameter>libc_cv_c_cleanup=yes</parameter></term>
         <listitem>
-          <para>The build also requires support for C cleanup handling, which it
-          cannot auto detect when being cross compiled. Enable it explicitly.</para>
+          <para>Simlarly, we pass libc_cv_c_cleanup=yes through to the
+          <command>configure</command> script so that the test is skipped and C
+          cleanup handling support is configured.</para>
         </listitem>
       </varlistentry>