These are based on C23's <stdbit.h>.

Signed-off-by: Alejandro Colomar <alx@nginx.com>

Related to:

    HTTP: compress: gzip

Signed-off-by: Alejandro Colomar <alx@nginx.com>

Signed-off-by: Alejandro Colomar <alx@nginx.com>

Signed-off-by: Alejandro Colomar <alx@nginx.com>

There are still no supported encodings.  This is just infrastructure for
the next commits, which will add gzip compression.

Signed-off-by: Alejandro Colomar <alx@nginx.com>

nxt_min()
nxt_max()
    Return the minimum/maximum of two values.

nxt_swap()
    Swap the values of two variables passed by their addresses.

nxt_sizeof_array()
    Return the size (in bytes) of an array.

nxt_nitems()
    Return the number of elements in an array.

nxt_memberof()
    Expand to a member of a structure.  It uses a compound literal for
    the object.

nxt_sizeof_incomplete()
    Calculate the size of an incomplete type, as if sizeof() could be
    applied to it.

nxt_sizeof_fam0()
    Calculate the size of each element of a FAM of a structure.

nxt_sizeof_fam()
    Calculate the size of a FAM of a structure.

nxt_offsetof_fam()
    Calculate the offset of the nth element of the FAM from the start of
    the containing structure.

nxt_sizeof_struct()
    Calculate the total size of a structure containing a FAM.  This
    value is the one that should be used for allocating the structure.

    Suggested-by: Andrew Clayton <a.clayton@nginx.com>

nxt_is_near_end()
    Evaluate to true if the member is near the end of a structure.  This
    is only designed to be used with FAMs, to make sure that the FAM is
    near the end of the structure (a zero-length array near the end of
    the structure would still pass this test, but it's a reasonable
    assertion to do.

    Suggested-by: David Laight <David.Laight@ACULAB.COM>

nxt_is_zero_sizeof()
    Evaluate to true if the size of 'x' is 0.

nxt_is_same_type()
    Evaluate to true if the both arguments are compatible types.

nxt_is_same_typeof()
    Evaluate to true if the types of both arguments are compatible.

nxt_is_array()
    Evaluate to true if the argument is an array.

nxt_must_be()
    It's like static_assert(3), but implemented as an expression.  It's
    necessary for writing the must_be_array() macro.  It's always
    evaluates to (int) 0.

nxt_must_be_array()
    Statically assert that the argument is an array.  It is an
    expression that always evaluates to (int) 0.

nxt_must_be_zero_sizeof()
    Statically assert that the argument has a size of 0.

nxt_must_be_near_end()
    Statically assert that a member of a structure is near the end of
    it.

    Suggested-by: David Laight <David.Laight@ACULAB.COM>

nxt_must_be_fam()
    Statically assert that the argument is a flexible array member
    (FAM).  It's an expression that always evaluates to (int) 0.

Link: <https://gustedt.wordpress.com/2011/03/14/flexible-array-member/>
Link: <https://lore.kernel.org/lkml/202308161913.91369D4A@keescook/T/>
Link: <https://inbox.sourceware.org/gcc/dac8afb7-5026-c702-85d2-c3ad977d9a48@kernel.org/T/>
Link: <https://stackoverflow.com/a/57537491>
Link: <https://github.com/shadow-maint/shadow/pull/762>
Cc: Andrew Clayton <a.clayton@nginx.com>
Cc: Zhidao Hong <z.hong@f5.com>
Signed-off-by: Alejandro Colomar <alx@nginx.com>

This allows to configure the Wasm module, e.g

  ./configure wasm --include-path=/path/to/wasmtime-v11.0.0-x86_64-linux-c-api/include --lib-path=/path/to/wasmtime-v11.0.0-x86_64-linux-c-api/lib --rpath

--rpath as above says to set the rpath to the value of --lib-path. You
can alternatively specify a directory to use as the rpath. Or simply
omit the option to not have an rpath set.

This is mostly useful for during development where you may not have the
Wasmtime stuff installed to system directories or you want to test with
newer/different versions.

See ./configure wasm --help for a full list of options.

Reviewed-by: Alejandro Colomar <alx@nginx.com>
Signed-off-by: Andrew Clayton <a.clayton@nginx.com>