Split the bit acinclude.m4 file into smaller pieces named
as m4/virt-XXXXX.m4
* .gitignore: Ignore gettext related files
* acinclude.m4: Delete
* m4/virt-compile-warnings.m4: Checks for GCC compiler flags
* m4/virt-pkgconfig-back-compat.m4: Backcompat check for
pkgconfig program
