libreoffice: fix cross build where sizeof(long) is different

srcpkgs/libreoffice/patches/006-cross-flag.patch

@@ -5,9 +5,11 @@ Description: Perhaps cleanup a bit and submit to upstream
  environment during build.
 --- a/configure.ac
 +++ b/configure.ac
-@@ -6046,10 +6046,11 @@ if test "$cross_compiling" = "yes"; then
+@@ -6051,11 +6051,13 @@
+     cp configure CONF-FOR-BUILD
      test -d config_build && cp -p config_build/*.h CONF-FOR-BUILD/config_host 2>/dev/null
      (
++    unset ${!ac_*}
      unset COM USING_X11 OS CPUNAME
 -    unset CC CXX SYSBASE CFLAGS
 +    unset CC CXX SYSBASE CFLAGS CXXFLAGS CPP CPPFLAGS LD LDFLAGS
@@ -18,7 +20,7 @@ Description: Perhaps cleanup a bit and submit to upstream
      unset PKG_CONFIG_LIBDIR PKG_CONFIG_PATH
      if test -n "$CC_FOR_BUILD"; then
          export CC="$CC_FOR_BUILD"
-@@ -6059,6 +6060,12 @@ if test "$cross_compiling" = "yes"; then
+@@ -6065,6 +6067,12 @@
          export CXX="$CXX_FOR_BUILD"
          CXX_BASE=`first_arg_basename "$CXX"`
      fi