[Qt][Mac] Remove obsolete workaround for debug builds
https://bugs.webkit.org/show_bug.cgi?id=114750

Reviewed by Jocelyn Turcotte.

This workaround made default builds fail with recent Qt5 because
it removed the major version number from the library name, producing
QtWebKitWidgets, whereas the linking command line tried to link
against Qt5WebKitWidgets.
Debug builds are possible with and without framework-enabled builds
of Qt, but the debug versions of the Qt libraries have to be present.
Debug builds with a release version of Qt are not possible on Mac
since for debug builds qmake produces a linker command line where
all the Qt libraries have the "_debug" suffix, therefore if the debug
libraries are missing the build fails.

* Source/widgetsapi.pri:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148789 268f45cc-cd09-0410-ab3c-d52691b4dbfc
LLint should be able to use x87 instead of SSE for floating pointer
https://bugs.webkit.org/show_bug.cgi?id=112239

Reviewed by Filip Pizlo.

Source/JavaScriptCore:

Implements LLInt floating point operations in x87, to ensure we support
x86 without SSE2.

X86 (except 64bit) now defaults to using x87 instructions in order to
support all 32bit x86 back to i686. The implementation uses the fucomi
instruction from i686 which sets the new minimum.

The FPU registers must always be empty on entering or exiting a function.
We make sure to only use two X87 registers, and they are always emptied
before calling deeper functions or returning from the LLInt.

* jit/JITStubs.cpp:
(JSC): Empty FPU registers before exiting.
* llint/LowLevelInterpreter32_64.asm:
* llint/LowLevelInterpreter64.asm:
* offlineasm/instructions.rb:
* offlineasm/x86.rb:

Source/WTF:

Disable GTK workaround now that LLInt does not require SSE2.

* wtf/Platform.h:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148790 268f45cc-cd09-0410-ab3c-d52691b4dbfc