autoconf-nativesdk: fix builds on fedora 17

Generally distros keep perl at /usr/bin/perl
Fedora 17 also has /bin/perl

this causes autoconf-nativesdk build on such distros to put perl
interpreter path in the perl scripts as /bin/perl

But we set perl location for target as /usr/bin/perl

This mismatch of perl path causes failure of rootfs image creation
like this:

| error: Failed dependencies:
|       /bin/perl is needed by autoconf-nativesdk-2.68-r6.x86_64.rpm
NOTE: package meta-toolchain-gmae-1.0-r7: task do_populate_sdk: Failed

The second sed command is for such a case:

eval 'case $# in 0) exec /bin/perl -S "$0";; *) exec /bin/perl -S "$0" "$@";; esac'

This line has two "/bin/perl" and we can't use a line number to tell
sed which line it is since the line numbers in different files are
defferent.

[YOCTO #2304]

(From OE-Core rev: 393908e53b243b16ab984da7f073be371e062946)

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/autoconf/autoconf.inc

@@ -17,6 +17,20 @@ SRC_URI = "${GNU_MIRROR}/autoconf/autoconf-${PV}.tar.bz2 \
 
 inherit autotools
 
+PERLPATH = "${bindir}/perl"
+PERLPATH_virtclass-native = "/usr/bin/perl"
+PERLPATH_virtclass-nativesdk = "/usr/bin/perl"
+
 do_install_append() {
-	rm -rf ${D}${datadir}/emacs
+    rm -rf ${D}${datadir}/emacs
+
+    # Some distros have both /bin/perl and /usr/bin/perl, but we set perl location
+    # for target as /usr/bin/perl, so fix it to /usr/bin/perl.
+    for i in autoheader autom4te autoreconf autoscan autoupdate ifnames; do
+        if [ -f ${D}${bindir}/$i ]; then
+            sed -i -e '1s,#!.*perl,#! ${PERLPATH},' \
+            -e 's,exec .*/bin/perl \(.*\) exec .*/bin/perl \(.*\),exec ${PERLPATH} \1 exec ${PERLPATH} \2,' \
+            ${D}${bindir}/$i
+        fi
+    done
 } 

meta/recipes-devtools/autoconf/autoconf_2.68.bb

@@ -1,6 +1,6 @@
 require autoconf.inc
 
-PR = "r6"
+PR = "r7"
 
 PARALLEL_MAKE = ""