[PATCH 01/25] fix check for libdir in ldconfig paths

[Carl Worth]

On Sat, 28 May 2011 14:51:36 -0700, Jameson Graef Rollins <jrollins at finestructure.net> wrote:
> The configure script tries to check that the libdir is included in the
> ldconfig paths, and then sets the RPATH compiler flag if it's not.
> This check was broken, and was always setting RPATH.  This fixes the
> path check.

Thanks for the patch. I was intrigued about what was actually broken
here, so tracked down the problem and fixed it with an alternate patch
(see below).

-Carl

commit 574f408816e636f677b14384c18cc2e388991411
Author: Carl Worth <cworth at cworth.org>
Date:   Wed Jun 1 13:02:58 2011 -0700

    configure: Fix detection of libdir in ldconfig configuration
    
    Ever since commit b4b5e9ce4dac62111ec11da6d22b7e618056801f the
    detection of libdir in the ldconfig configuration has been broken,
    resulting in RPATH being set when not needed and not wanted.
    
    The cause was a change from an IFS setting of:
    
    	IFS="$(printf '\n\t')"
    
    to a new setting of:
    
    	IFS="$(printf '\n')"
    
    That looks desirable since we want to split the output of ldconfig
    based on newlines, (and not split on any filename that might have an
    embedded tab in it). The subtle bug in the above is that the shell
    trims any trailing newlines when performing command substitution so
    the final statement above was equivalent to:
    
    	IFS=''
    
    which prevented any splitting of the ldconfig output at all.
    
    Fix this by avoiding command substitution and just using a literal
    newline in the source file for setting this variable.

diff --git a/configure b/configure
index bbf30cd..cf525c9 100755
--- a/configure
+++ b/configure
@@ -355,17 +355,30 @@ elif [ $uname = "Linux" ] ; then
     printf "Linux\n"
     platform=LINUX
     linker_resolves_library_dependencies=1
+
+    printf "Checking for $libdir_expanded in ldconfig... "
     ldconfig_paths=$(/sbin/ldconfig -N -X -v 2>/dev/null | sed -n -e 's,^\(/.*\):\( (.*)\)\?$,\1,p')
     # Separate ldconfig_paths only on newline (not on any potential
-    # embedded space characters in any filenames).
+    # embedded space characters in any filenames). Note, we use a
+    # literal newline in the source here rather than something like:
+    #
+    #	IFS=$(printf '\n')
+    #
+    # because the shell's command substitution deletes any trailing newlines.
     OLD_IFS=$IFS
-    IFS="$(printf '\n')"
+    IFS="
+"
     for path in $ldconfig_paths; do
 	if [ "$path" = "$libdir_expanded" ]; then
 	    libdir_in_ldconfig=1
 	fi
     done
     IFS=$OLD_IFS
+    if [ "$libdir_in_ldconfig" = '0' ]; then
+	printf "No (will set RPATH)\n"
+    else
+	printf "Yes\n"
+    fi
 else
     printf "Unknown.\n"
     cat <<EOF
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