Fixing hashLog error 2^26=64Mib

Fix Appveyor failure

Optimized loop bounds to allow the compiler to unroll the loop.

RLE test and re-enable RLE in main compression loop

shared library: rename import library with .dll.a extension

mort of open source project are using this extension for the import library.
The Win32 linker is supporting this extension, see
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/4/html/Using_ld_the_GNU_Linker/win32.html
section "direct linking to a dll"

This has no measurable impact on large files but improves small file
decompression by ~1-2% for 10kB, benchmarked with:

head -c 10000 silesia.tar > /tmp/test
make CC=/usr/local/bin/clang-9 BUILD_STATIC=1 && ./lzbench -ezstd -t1,5 /tmp/test

Superblocks rebased for merge

Method to get dictionary header size

Specs. clarifications for Block_Maximum_Size

as a follow up of #1882

Change c90 to c89

Fix parameter selection and adjustment with srcSize == 0

This reverts commit a152b4c67a5266f611db4a2eac4a79003852a795.

c89 and c90 are the same language. Old compilers like gcc 4.2.1 don't
know the c90 alias.

check that the dictBuilder can be compiled
with only lib/common and lib/compress as dependencies.