meson: pass correct endian in the cross file

Meson doesn't care for the value of the endian field, but packages may want to
use it and Meson master now validates the value.

Use siteinfo to obtain the endianism and write the correct value.

(From OE-Core rev: 2f9adf05efdddf8dae9c58976ae56cf32d9e57f0)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/meson.bbclass

@@ -1,4 +1,4 @@
-inherit python3native
+inherit siteinfo python3native
 
 DEPENDS_append = " meson-native ninja-native"
 
@@ -31,10 +31,6 @@ MESON_C_ARGS = "${MESON_TOOLCHAIN_ARGS} ${CFLAGS}"
 MESON_CPP_ARGS = "${MESON_TOOLCHAIN_ARGS} ${CXXFLAGS}"
 MESON_LINK_ARGS = "${MESON_TOOLCHAIN_ARGS} ${LDFLAGS}"
 
-# both are required but not used by meson
-MESON_HOST_ENDIAN = "bogus-endian"
-MESON_TARGET_ENDIAN = "bogus-endian"
-
 EXTRA_OEMESON_append = " ${PACKAGECONFIG_CONFARGS}"
 
 MESON_CROSS_FILE = ""
@@ -59,6 +55,16 @@ def meson_cpu_family(var, d):
     else:
         return arch
 
+def meson_endian(prefix, d):
+    arch, os = d.getVar(prefix + "_ARCH"), d.getVar(prefix + "_OS")
+    sitedata = siteinfo_data_for_machine(arch, os, d)
+    if "endian-little" in sitedata:
+        return "little"
+    elif "endian-big" in sitedata:
+        return "big"
+    else:
+        bb.fatal("Cannot determine endianism for %s-%s" % (arch, os))
+
 addtask write_config before do_configure
 do_write_config[vardeps] += "MESON_C_ARGS MESON_CPP_ARGS MESON_LINK_ARGS CC CXX LD AR NM STRIP READELF"
 do_write_config() {
@@ -86,13 +92,13 @@ gtkdoc_exe_wrapper = '${B}/gtkdoc-qemuwrapper'
 system = '${HOST_OS}'
 cpu_family = '${@meson_cpu_family('HOST_ARCH', d)}'
 cpu = '${HOST_ARCH}'
-endian = '${MESON_HOST_ENDIAN}'
+endian = '${@meson_endian('HOST', d)}'
 
 [target_machine]
 system = '${TARGET_OS}'
 cpu_family = '${@meson_cpu_family('TARGET_ARCH', d)}'
 cpu = '${TARGET_ARCH}'
-endian = '${MESON_TARGET_ENDIAN}'
+endian = '${@meson_endian('TARGET', d)}'
 EOF
 }