use cross-prefix for pkgconfig

Since pkgconfig can give different output for different targets,
it should be tried with the cross-compilation prefix first.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

configure

@@ -965,6 +965,15 @@ EOF
   fi
 fi
 
+##########################################
+# pkgconfig probe
+
+pkgconfig="${cross_prefix}pkg-config"
+if ! test -x "$(which $pkgconfig 2>/dev/null)"; then
+  # likely not cross compiling, or hope for the best
+  pkgconfig=pkg-config
+fi
+
 ##########################################
 # Sparse probe
 if test "$sparse" != "no" ; then
@@ -1048,8 +1057,8 @@ if test "$vnc_tls" != "no" ; then
 #include <gnutls/gnutls.h>
 int main(void) { gnutls_session_t s; gnutls_init(&s, GNUTLS_SERVER); return 0; }
 EOF
-  vnc_tls_cflags=`pkg-config --cflags gnutls 2> /dev/null`
-  vnc_tls_libs=`pkg-config --libs gnutls 2> /dev/null`
+  vnc_tls_cflags=`$pkgconfig --cflags gnutls 2> /dev/null`
+  vnc_tls_libs=`$pkgconfig --libs gnutls 2> /dev/null`
   if compile_prog "$vnc_tls_cflags" "$vnc_tls_libs" ; then
     vnc_tls=yes
     libs_softmmu="$vnc_tls_libs $libs_softmmu"
@@ -1321,7 +1330,7 @@ if test "$check_utests" != "no" ; then
 #include <check.h>
 int main(void) { suite_create("qemu test"); return 0; }
 EOF
-  check_libs=`pkg-config --libs check`
+  check_libs=`$pkgconfig --libs check`
   if compile_prog "" $check_libs ; then
     check_utests=yes
     libs_tools="$check_libs $libs_tools"
@@ -1340,8 +1349,8 @@ if test "$bluez" != "no" ; then
 #include <bluetooth/bluetooth.h>
 int main(void) { return bt_error(0); }
 EOF
-  bluez_cflags=`pkg-config --cflags bluez 2> /dev/null`
-  bluez_libs=`pkg-config --libs bluez 2> /dev/null`
+  bluez_cflags=`$pkgconfig --cflags bluez 2> /dev/null`
+  bluez_libs=`$pkgconfig --libs bluez 2> /dev/null`
   if compile_prog "$bluez_cflags" "$bluez_libs" ; then
     bluez=yes
     libs_softmmu="$bluez_libs $libs_softmmu"