internal/rosa/package: migrate gcc

The azalea implementation used an adaptation of this as testdata.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/package/gcc/musl-off64_t-loff_t.patch

@@ -0,0 +1,16 @@
+diff --git a/libgo/sysinfo.c b/libgo/sysinfo.c
+index 180f5c31d74..44d7ea73f7d 100644
+--- a/libgo/sysinfo.c
++++ b/libgo/sysinfo.c
+@@ -365,11 +365,7 @@ enum {
+ typedef loff_t libgo_loff_t_type;
+ #endif
+
+-#if defined(HAVE_OFF64_T)
+-typedef off64_t libgo_off_t_type;
+-#else
+ typedef off_t libgo_off_t_type;
+-#endif
+
+ // The following section introduces explicit references to types and
+ // constants of interest to support bootstrapping libgo using a