Add C++ mangling of struct and class names for member variables and functions
Add backend-independent stub glue layer
Replace another rename macro with an #ifdef
Replace unnecessary #define with #ifdef
Remove unnecessary initializer list
Merge pull request #2022 from yebblies/deadcode2

[DDMD] Remove unnecessary initializer list
fix Issue 10056 - Strange Error with templates and string.format

If IFTI error is gagged (`(flags&1) != 0` in deduceTemplateFunction), function body semantic should be delayed, as same as `FuncDeclaration::overloadResolve` do.

For the lazily function semantic, hasIdentity(Assign|Equals) should not allocate arguments `Expressions` on stack.
Replace global.structalign with STRUCTALIGN_DEFAULT
Merge pull request #2013 from 9rnsr/fix10056

[REG2.063a] Issue 10056 - Strange Error with templates and string.format
Merge pull request #2023 from yebblies/structalign

[DDMD] Replace global.structalign with STRUCTALIGN_DEFAULT
Merge pull request #2012 from yebblies/gluestub

[DDMD] Add backend-independent stub glue layer
Merge pull request #1990 from yebblies/manglemembers

[DDMD] [C++] Add C++ mangling of struct and class names for member variables and functions
Merge pull request #2019 from yebblies/writewchar

[DDMD] Replace another rename macro with an #ifdef
Merge pull request #2018 from yebblies/snprintf

[DDMD] Replace unnecessary #define with #ifdef