glib-2.0: fix builds on fedora 17

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

this causes glib-2.0 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 libglib-2.0-utils-2.30.3-r0.ppc603e
NOTE: package meta-toolchain-gmae-1.0-r7: task do_populate_sdk: Failed

[YOCTO #2304]

(From OE-Core rev: 13e6e316d751d0ea3107d5547f6bdd2b74919cad)

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

meta/recipes-core/glib-2.0/glib-2.0_2.30.3.bb

@@ -1,6 +1,6 @@
 require glib.inc
 
-PR = "r0"
+PR = "r1"
 PE = "1"
 
 DEPENDS += "libffi python-argparse-native zlib"
@@ -25,6 +25,10 @@ SRC_URI_append_libc-uclibc = " ${@['', 'file://no-iconv.patch']['${PN}' == '${BP
 SRC_URI_append_virtclass-native = " file://glib-gettextize-dir.patch"
 BBCLASSEXTEND = "native nativesdk"
 
+PERLPATH = "${bindir}/env perl"
+PERLPATH_virtclass-native = "/usr/bin/env perl"
+PERLPATH_virtclass-nativesdk = "/usr/bin/env perl"
+
 do_configure_prepend() {
   # missing ${topdir}/gtk-doc.make and --disable-gtk-doc* is not enough, because it calls gtkdocize (not provided by gtk-doc-native)
   sed -i '/^docs/d' ${S}/configure.ac
@@ -39,6 +43,12 @@ do_install_append() {
   # and empty dirs
   rmdir ${D}${libdir}/gio/modules/
   rmdir ${D}${libdir}/gio/
+
+  # 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.
+  if [ -f ${D}${bindir}/glib-mkenums ]; then
+    sed -i -e '1s,#!.*perl,#! ${PERLPATH},' ${D}${bindir}/glib-mkenums
+  fi
 }
 
 PACKAGES += "${PN}-codegen"