std.conv: Fix ambiguity when target has ctor and source has opCast
std.array: Allow joining constant arrays
fix Issue 1832 - rebuilding ZipArchive looses data

- Already need to set compressedData slice when reading
  the directory index not only during expand.
Fix Issue 4725 - std.algorithm.sum()
Document use of Kahan vs. vanilla summation
Added LREF to sum in reduce
pairwise sum returns double for ranges with float elements
Fix Issue 12003 - std\zip.d(421): Deprecation
std.stdio: Fix generating documentation on POSIX

Declare a dummy HANDLE alias to allow the compilation of the
Windows-only File methods.
std.net.curl: Publicly import CurlOption
fix Issue 12098 - libcurl bad argument on handle null
Merge pull request #1920 from 9rnsr/fix12098

[REG2.065a] Issue 12098 - libcurl bad argument on handle null
Convert to new alias syntax
Merge pull request #1926 from 9rnsr/new_alias_syntax

Convert to new alias syntax
Remove package function `defaultInit`

It was a hack for the compiler bugs around T.init. Now the they are properly fixed, so the unused helper function is actually unnecessary.
Fix predicate template implementations in std.traits and std.range

Use T.init property instead of void initializer, because it will work even if T is const or immutable type.

I must change a part of unit test for the bug 6935, because we cannot support ranges which overrides init property.
Add a test case isAssignable!(void[1], void[1])
fix Issue 12071 - Algebraic won't take delegate returning structure

Use `Variant` rather than `VariantN` in order to pack arguments and returned value in opCall.
Regression Test 8282 - new Array!T

This one doesn't have an equivalent test, so adding this to make sure the bug never comes back. The actual issue was fixed in 2.063.

https://d.puremagic.com/issues/show_bug.cgi?id=8282
std.stdio: Add File.windowsHandle, fdopen and windowsHandleOpen

This moves existing code from std.process to std.stdio for public use.