Imported from libpng-1.2.9beta7.tar

aclocal.m4

@@ -219,6 +219,14 @@ AC_ARG_WITH([pic],
     [pic_mode=default])
 test -z "$pic_mode" && pic_mode=default
 
+# Check if we have a version mismatch between libtool.m4 and ltmain.sh.
+#
+# Note:  This should be in AC_LIBTOOL_SETUP, _after_ $ltmain have been defined.
+#        We also should do it _before_ AC_LIBTOOL_LANG_C_CONFIG that actually
+#        calls AC_LIBTOOL_CONFIG and creates libtool.
+#
+_LT_VERSION_CHECK
+
 # Use C for the default configuration in the libtool script
 tagname=
 AC_LIBTOOL_LANG_C_CONFIG
@@ -226,6 +234,41 @@ _LT_AC_TAGCONFIG
 ])# AC_LIBTOOL_SETUP
 
 
+# _LT_VERSION_CHECK
+# -----------------
+AC_DEFUN([_LT_VERSION_CHECK],
+[AC_MSG_CHECKING([for correct ltmain.sh version])
+if test "x$ltmain" = "x" ; then
+  AC_MSG_RESULT(no)
+  AC_MSG_ERROR([
+
+*** @<:@Gentoo@:>@ sanity check failed! ***
+*** \$ltmain is not defined, please check the patch for consistency! ***
+])
+fi
+gentoo_lt_version="1.5.22"
+gentoo_ltmain_version=`sed -n '/^[[ 	]]*VERSION=/{s/^[[ 	]]*VERSION=//;p;q;}' "$ltmain"`
+if test "x$gentoo_lt_version" != "x$gentoo_ltmain_version" ; then
+  AC_MSG_RESULT(no)
+  AC_MSG_ERROR([
+
+*** @<:@Gentoo@:>@ sanity check failed! ***
+*** libtool.m4 and ltmain.sh have a version mismatch! ***
+*** (libtool.m4 = $gentoo_lt_version, ltmain.sh = $gentoo_ltmain_version) ***
+
+Please run:
+
+  libtoolize --copy --force
+
+if appropriate, please contact the maintainer of this
+package (or your distribution) for help.
+])
+else
+  AC_MSG_RESULT(yes)
+fi
+])# _LT_VERSION_CHECK
+
+
 # _LT_AC_SYS_COMPILER
 # -------------------
 AC_DEFUN([_LT_AC_SYS_COMPILER],
@@ -1356,6 +1399,30 @@ cygwin* | mingw* | pw32*)
     esac
     ;;
 
+  linux*)
+    if $LD --help 2>&1 | egrep ': supported targets:.* elf' > /dev/null; then
+      archive_cmds='$CC -shared $libobjs $deplibs $compiler_flags ${wl}-soname $wl$soname -o $lib'
+      supports_anon_versioning=no
+      case `$LD -v 2>/dev/null` in
+        *\ [01].* | *\ 2.[[0-9]].* | *\ 2.10.*) ;; # catch versions < 2.11
+        *\ 2.11.93.0.2\ *) supports_anon_versioning=yes ;; # RH7.3 ...
+        *\ 2.11.92.0.12\ *) supports_anon_versioning=yes ;; # Mandrake 8.2 ...
+        *\ 2.11.*) ;; # other 2.11 versions
+        *) supports_anon_versioning=yes ;;
+      esac
+      if test $supports_anon_versioning = yes; then
+        archive_expsym_cmds='$echo "{ global:" > $output_objdir/$libname.ver~
+cat $export_symbols | sed -e "s/\(.*\)/\1;/" >> $output_objdir/$libname.ver~
+$echo "local: *; };" >> $output_objdir/$libname.ver~
+        $CC -shared $libobjs $deplibs $compiler_flags ${wl}-soname $wl$soname ${wl}-version-script ${wl}$output_objdir/$libname.ver -o $lib'
+      else
+        $archive_expsym_cmds="$archive_cmds"
+      fi
+    else
+      ld_shlibs=no
+    fi
+    ;;
+
   *)
     library_names_spec='${libname}`echo ${release} | $SED -e 's/[[.]]/-/g'`${versuffix}${shared_ext} $libname.lib'
     ;;
@@ -1420,7 +1487,14 @@ freebsd* | dragonfly*)
     *) objformat=elf ;;
     esac
   fi
-  version_type=freebsd-$objformat
+  # Handle Gentoo/FreeBSD as it was Linux
+  case $host_vendor in
+    gentoo)
+      version_type=linux ;;
+    *)
+      version_type=freebsd-$objformat ;;
+  esac
+
   case $version_type in
     freebsd-elf*)
       library_names_spec='${libname}${release}${shared_ext}$versuffix ${libname}${release}${shared_ext} $libname${shared_ext}'
@@ -1431,6 +1505,12 @@ freebsd* | dragonfly*)
       library_names_spec='${libname}${release}${shared_ext}$versuffix $libname${shared_ext}$versuffix'
       need_version=yes
       ;;
+    linux)
+      library_names_spec='${libname}${release}${shared_ext}$versuffix ${libname}${release}${shared_ext}$major ${libname}${shared_ext}'
+      soname_spec='${libname}${release}${shared_ext}$major'
+      need_lib_prefix=no
+      need_version=no
+      ;;
   esac
   shlibpath_var=LD_LIBRARY_PATH
   case $host_os in