scons duplicate environment warnings on Windows

[Sean M. Pappalardo]

When building recent versions of the 1.11 branch (I don't know exactly when this started because I've been away for awhile,) scons reports the following error on all Soundtouch files:

scons: warning: Two different environments were specified for target C:\Mixxx\Branches\1.11\mixxx\lib\soundtouch-1.6.0\SoundTouch.obj,
        but they appear to have the same action: ${TEMPFILE("$SHCXX $_MSVC_OUTPUT_FLAG /c $CHANGED_SOURCES $SHCXXFLAGS $SHCCFLAGS $_CCCOMCOM")}
File "C:\Mixxx\Branches\1.11\mixxx\src\SConscript", line 61, in <module>

It persists even if I delete scons' cache and the build directory (doing a clean build.)

Nothing jumped out at me looking near that line in the SConscript.

[RJ Skerry-Ryan (rryan)]

I think I fixed this.

[RJ Skerry-Ryan (rryan)]

Apparently this error turned fatal at some point (newer scons version?) so I'm reviving my old fix (which I had rolled back).

[RJ Skerry-Ryan (rryan)]

https://github.com/mixxxdj/mixxx/commit/85893d1d134a72c04cb085e97786ff97146b201b

[Sébastien BLAISOT (sblaisot)]

scons failure was not due to these warnings.

[RJ Skerry-Ryan (rryan)]

https://github.com/mixxxdj/mixxx/pull/1835

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/6938