buildconf: fix libtool 1.5.x warnings triggered with autoconf 2.6x or later

Using libtool 1.5.x (x < 26) with autoconf 2.6x or later generates warnings
due to some libtool variables not following naming convention for variables
that will be cached.

This is addressed renaming a couple of variables to make these follow expected
naming convention.

diff --git a/buildconf b/buildconf
index bdd1712..bc448f9 100755 (executable)
--- a/buildconf
+++ b/buildconf
@@ -276,6 +276,10 @@ fi
 # perl check
 #
 PERL=`findtool ${PERL:-perl}`
+if test -z "$PERL"; then
+  echo "buildconf: perl not found"
+  exit 1
+fi
 
 #--------------------------------------------------------------------------
 # Remove files generated on previous buildconf/configure run.
@@ -311,6 +315,7 @@ for fname in .deps \
     libcurl.pc \
     libtool \
     libtool.m4 \
+    libtool.m4.bak \
     ltmain.sh \
     ltoptions.m4 \
     ltsugar.m4 \
@@ -329,6 +334,16 @@ done
 echo "buildconf: running libtoolize"
 $libtoolize --copy --automake --force || die "The libtoolize command failed"
 
+if test "$lt_major" = "1" && test "$lt_minor" = "5"; then
+  if test -z "$lt_patch" || test "$lt_patch" -lt "26"; then
+    echo "buildconf: running libtoolize hack to rename some variables"
+    $PERL -i.bak -pe \
+      's/lt_prog_compiler_pic_works/lt_cv_prog_compiler_pic_works/g; \
+       s/lt_prog_compiler_static_works/lt_cv_prog_compiler_static_works/g;' \
+      m4/libtool.m4
+  fi
+fi
+
 if test ! -f m4/curl-functions.m4; then
   echo "buildconf: cURL m4 macros not found"
   exit 1