Avoid quoting dependency filepaths in build tree

Avoid quoting dependency filepaths in build tree

C++Builder's `make.exe` has a bug in finding the rule of a quoted
dependency that doesn't exist in the filesystem. So for example:

    A: "src\B" "out\C"
    	touch $@
    out\C:
    	mkdir out
    	touch $@

leads to:
    Fatal: '"out\C"' does not exist - don't know how to make it

This happens even with the `-N` option, and is different behavior from
Microsoft NMake which documents the feature of [quoted filepaths][1].

Commit cb663908 quoted all dependency filepaths, in case they are used
in a out-of-source build. The quoting is not done for target names,
however, which implies that the build directory is still expected to not
have spaces. It follows that we only need to quote non-generated source
files in dependency lists, since generated source files will be created
in the build directory.

Change the logic accordingly as a workaround, so that it works at least
for in-source builds with C++Builder's `make.exe`.

[1]: https://docs.microsoft.com/cpp/build/reference/long-filenames-in-a-makefile?view=msvc-160

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/13540)