Merge pull request #3780 from 9rnsr/fix13141

[REG2.066a] Issue 13141 - array cast from string[] to immutable(char[][]) is not supported at compile time
Merge pull request #3779 from 9rnsr/fix13142

Issue 13142 - Enums on different classes confuse the compiler
Merge pull request #3778 from MartinNowak/fix13117

fix Issue 13117 - Executable size of hello world explodes from 472K to 2.7M
Merge pull request #3777 from 9rnsr/fix13030

[REG2.064] Issue 13030 - DMD assertion fails at mtype.c:697 if delegate has an argument name
Merge pull request #3781 from 9rnsr/2.066

Cherry-picking commits from master to 2.066 branch (for beta5)