remove automatic splitting from $$() expansions

$$(FOO) would automatically split the contents of the environment
variable at whitespace (and interpret quoting inside it). the way to
prevent the splitting (but not the quote interpretation) would be using
"$$(FOO)".

this behavior is entirely unexpected and thus an incredibly effective
source of quoting problems - according to a grep over the whole qt
sources, there isn't a single case where things were done right. in qt
creator, well over half the cases are wrong.

also, the "feature" seems entirely pointless: nobody uses spaces as
separators in environment variables.

consequently, simply remove it, even in a patch release. i'm postulating
that nobody will complain.

Change-Id: I9ed3df1b0d1ef602acd78ceb118611d294561da6
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
(cherry picked from qtbase/566d28316dd73bfe4a8ea34839989ee9df7e3895)
Update feature paths on assignment to QMAKE_PLATFORM

Instead of after parsing the makespecs, were we assumed QMAKE_PLATFORM
had been set by the makespec and did an explicit update.

Allows loading platform specific features from within a makespec after
updating QMAKE_PLATFORM.

Change-Id: I0eb3b7fb88ce48b00a384850c5d87223c06234d7
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>
(cherry picked from qtbase/4dd29248cd43ff730f7432b51a443b72fad3523d)
remove pointless initialization of qmakespec

we have proper fallback paths further down the line.

Change-Id: I3648cc985d21bbec4c2c24e179830db4467af210
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
(cherry picked from qtbase/0dedf8c3403923b963c51eb65d9cbe838d5ba0d4)
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
permit returning from files

this allows skipping an entire feature file if a condition is not
fulfilled, without putting the whole body inside a conditional.

Change-Id: I84fe9c94dda58c794fb52c3f163b40563b0db30a
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
(cherry picked from qtbase/525eb337670f61078383c20ad9be274dcf2d0928)
make split_value_list() mostly sane

don't count parentheses, don't nest quotes, don't create empty elements.
the backslash still escapes only quotes (and itself) - $$list() (one of
the main users of this function) is commonly used with (windows) path
lists, so letting it escape anything would make a royal mess.

Change-Id: I29252fbe14fd6d28217450ec41cf8acfb2e30681
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
(cherry picked from qtbase/6c22b9b3e86d1617665f7b81b105c032f43c6d72)
(cherry picked from qtbase/a5c2ab47867a558d6f8f62126fb8e4f2777cfe06)
clean paths of found files in prepareProject()

any of the directories may be the root, which would lead to double slashes
in the constructed filenames.

Change-Id: I053e167a19b795b40e780fc29db356c7f24d286a
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
(cherry picked from qtbase/97be79012cd39d1d0e7748d5c500d86c3becc258)
don't send output of $$join() and $$sprintf() through split_value_list()

in the case of sprintf it's surprising, in the case of join it's
anti-thetical.

Change-Id: I4eb7e56d31ac6ed68adf852f1a19b33554d38eb4
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
(cherry picked from qtbase/ae94bf2b7a6373def9239ae5f54b143e1f6ffe09)