configure: Fix check_exec_crash for ICL support

Change the check_exec_crash test to use a function pointer instead of
simply calling the function. The EBP availability test will crash when
compiled with ICL likely due to compiler optimization shenanigans.

Originally the check_exec_crash code was moved out of main to fix a
problem with gcc's treatment of non-leaf main on x86_32. Libav already
moved the code out of main but the addition of the function pointer will
prevent any inlining which fixes the remaining problem.

A function pointer is used since it is compiler agnostic (as opposed to
say __attribute__ ((noinline)) which would only work with gcc compatible
compilers).

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
msvc/icl: Intel Compiler support on Windows

Initial support for the ICL compiler on windows. Requires a new
c99wrap with ICL support (1.0.2+).

Currently not much different speed wise compared to msvc. In the
future with a few changes it can be made to support the inline asm.
This would be the primary reason for using it.

Passed all fate tests, versions tested:
    13.1.1.171 (2013 Update 3) x86 and x64
    12.1.5.344 (2011 Update 11) x86 and x64

Signed-off-by: Luca Barbato <lu_zero@gentoo.org>