Separate Asterisk Version Support Into Independent Files #9
Description
Making changes to app_swift.c currently may have "knock-on" effects not intended for other versions of support.
For example, if a bug fix gets committed for Asterisk v18 it may conflict with v16 support, etc..
I propose that instead of using a long list of #if defined statements we separate the support for each version into its own source file.
The main app_swift.c can then #include the appropriate source file based on the CFLAGS provided when compiling.
This would also have the effect of making the source files easier to read and would make QOL improvements for development (notably proper syntax highlighting and function resolution in IDE's)