[OE-core] [PATCH] site: Add common-darwin

[Richard Purdie]

We need this to ensure there are some correct values when building with
meta-darwin. This matches the addition of a common-mingw site file in
the core.

diff --git a/meta/site/common-darwin b/meta/site/common-darwin
new file mode 100644
index 0000000..604c04b
--- /dev/null
+++ b/meta/site/common-darwin
@@ -0,0 +1,2 @@
+ac_cv_func_posix_getpwuid_r=${ac_cv_func_posix_getpwuid_r=yes}
+ac_cv_func_posix_getpwuid_r=${ac_cv_func_posix_getgrgid_r=yes}