XPCOM binary components imply dependent linkage, don't work with msvcrt
static linkage and have to be built against mozglue, so let's remove all
the footguns changing those add.
JS_STANDALONE builds don't need everything in mozglue; have mozglue omit the
unneeded code for such builds.
Since the SpiderMonkey binaries are now more like the other Gecko binaries, we
can remove some special cases for JS_STANDALONE in GeckoSharedLibrary,
GeckoProgram, etc. All Gecko binaries now use mozglue, which contains mfbt, so
we no longer need mention mfbt explicitly.
Add a property to the getBuildConfiguration testing function's result that
indicates whether we're using jemalloc or not.
Include the newly necessary source directories in the SpiderMonkey source
package.
There are, sadly, many combinations of linkage in use throughout the tree.
The main differentiator, though, is between program/libraries related to
Gecko or not. Kind of. Some need mozglue, some don't. Some need dependent
linkage, some standalone.
Anyways, these new templates remove the need to manually define the
right dependencies against xpcomglue, nspr, mozalloc and mozglue
in most cases.
Places that build programs and were resetting MOZ_GLUE_PROGRAM_LDFLAGS
or that build libraries and were resetting MOZ_GLUE_LDFLAGS can now
just not use those Gecko-specific templates.
