This patch automatically generates case macros such as:
CASE_CFN_SQRT
for each {F,,L} floating-point built-in function and each {,L,LL,IMAX}
integer built-in function. The macros match the same built-in
functions as CASE_FLT_FN and CASE_INT_FN but in addition include
the associated internal function, if any.
The idea is to make sure that users of combined_fn don't need to know
which built-in functions have internal-function equivalents. If we add
a new function to internal-fn.def, all combined_fn users should pick it
up automatically.
The generator wants to use "hash_set <nofree_string_hash>",
so the patch follows hash_map in using the types given by the
traits as the key. This is a no-op for current users of hash_set.
Tested on x86_64-linux-gnu, aarch64-linux-gnu and arm-linux-gnueabi.