[oe] [meta-qt5] qtscript,qtwebking: disable thumb issues on armv7

[Andreas Müller]

Hi

The story occured on jethro but I think it is the same for master:

We have a simple application containing a QWebView which segfaulted
during loading a page on a CortexA9 (armv7 thumb2). After enabling
debug information for qtwebkit and remote debug session the point of
segfault was detected in

qtwebkit: Source/JavaScriptCore/llint/LowLevelInterpreter.asm:1082
   callSlowPath(_llint_slow_path_new_func_exp)

Further digging around lead to similar source in:

* qtwebkit: Source/JavaScriptCore/assembler/ARMv7Assembler.h
* qtscript: src/3rdparty/javascriptcore/JavaScriptCore/assembler/ARMv7Assembler.h

In these files a class ARMThumbImmediate is declared and used in many
places. This lead me to the assumption that compiling for armv7
expects thumb support.

So I removed the

ARM_INSTRUCTION_SET = "arm"

and our application worked fine. To be a good boy I then build tested
with ARM_INSTRUCTION_SET = "thumb" and for qemuarm: It still fails.

So what would the right way to go? Something like the pending patch
for icu replacing

ARM_INSTRUCTION_SET = "arm"

by

ARM_INSTRUCTION_SET_armv4 = "arm"
ARM_INSTRUCTION_SET_armv5 = "arm"

Opinions?

Andreas