1445 – Add default library options to sc.ini / dmd.conf

It would be quite useful if the DMD configuration file provided a means of specifying the name of the default libraries to link based on the presence of "-release" on the command-line. In short, I'd like for something like this to happen:
* Specify "phobos.lib" as the library to use for release builds and "phobos_d.lib" as the library to use for debug builds.
* Command "dmd foo.d" links "phobos_d.lib" as specified in sc.ini
* Command "dmd -release foo.d" links "phobos.lib" as specified in sc.ini
If either of these fields are not set, the built-in default (phobos.lib or libphobos.a) will be used instead.
This has the advantage of both simplifying the use of alternate runtime libraries and providing a means of linking a debug lib when doing so may be beneficial to the user.

along the same line, it would be vary nice to be able to select phobos vs. tango builds. Something like have a DMDLIB environment variable that picks a section out of the sc.ini file.

I'll do this as command line switches, which can be set via DFLAGS in sc.ini/dmd.conf.

some part of this proposal seems to duplicate with bug 987
*** This bug has been marked as a duplicate of 987 ***

oh why not make the current -debuglib a little bit more advanced?
I mean make the -debuglib work together with -debug version , different debug
version uses different debuglib, 
and -g symbolic stuff should be also controllable with -debug version stuff, so the compiler debug system goes consistent

sorry for the bad mouse clicking, reopen this issue for a little bit more enhancement

This was added back in versions 1.021 and 2.004:
-debuglib=libname
 link in libname as the default library when compiling for
 symbolic debugging instead of libphobos2.a 
-defaultlib=libname
 link in libname as the default library when not compiling
 for symbolic debugging instead of libphobos2.a
It's based off the -g option rather than the -release option, but.. close enough.