lfs/chapter05/diffutils-exp.xml

<sect2>
<title>Command explanations</title>

<para><userinput>CPPFLAGS=-Dre_max_failures=re_max_failures2:</userinput> The
CPPFLAGS variable is a variable that's read by the cpp program (C 
PreProcessor). The value of this variable tells the preprocessor to 
replace every instance of re_max_failures it finds by re_max_failures2 
before handing the source file to the compiler itself for compilation. This 
package has problems linking statically on systems that run an older
Glibc version and this construction fixes that problem.</para>

<para><userinput>PR_PROGRAM=/usr/bin/pr:</userinput> When 'diff' is called
with the '-i' flag, it tries to find 'pr' at the location specified with the
PR_PROGRAM variable. By default, this variable points to '/bin/pr', but since
we install 'pr' in /usr/bin, we need to change this.</para>

</sect2>