fmodl is available on newer FreeBSD versions
Disable enhancement feature 7444

Existing issues:

http://d.puremagic.com/issues/show_bug.cgi?id=11276
To enforce slice + assign syntax `a[] = b[]` may cause problems with generic code.

http://d.puremagic.com/issues/show_bug.cgi?id=11244
A case yet difficult to make it clear - combination with operator overloading.
fix Issue 11238 - Codegen error when this is a ref parameter to the method

Revert a part of the fix for issue 2356, to avoid aliasing issue.
fix Issue 11251 - Not able to link (Previous Definition Different)

By #2540 , implicitly defined C main has been moved to __entrypoint module. But, the codegen generates ModuleInfo symbol for the module. And vibe.d has its own main function in library. Then, compiling uer progam with vibe.d library will cause the conflict of two ModuleInfo symbols of __entrypoint module.

Due to avoid ModuleInfo symbol generation for __entrypoint, I added a special case in Module::genobjfile function. But, I'm not sure that the change won't cause any other problems...
Merge pull request #2673 from 9rnsr/rev7444

[REG2.063] Disable enhancement feature 7444
Merge pull request #2682 from 9rnsr/fix11238

[REG2.063] Issue 11238 - Codegen error when this is a ref parameter to the method
Merge pull request #2685 from 9rnsr/fix11251

[REG2.064a] Issue 11251 - Not able to link (Previous Definition Different)
Merge pull request #2657 from dawgfoto/portMathFreeBSD

fmodl is available on newer FreeBSD versions