Re: [libvirt] [RESEND PATCHv3 1/3] build: restore operation of bit-rotted 'make cov'

'./autobuild.sh' with lcov installed discovered that our coverage support has been bit-rotting for a while.  This restores it back to a successful state, although I have not yet spent any time looking through the resulting files to look for low-hanging fruit in the unit test coverage front. * configure.ac: Clear COMPILER_FLAGS at right place. * Makefile.am (cov): Newer genhtml no longer likes plain -s. * m4/compiler-flags.m4 (gl_COMPILER_FLAGS): Don't AC_SUBST COMPILER_FLAGS; it is a shell variable for use in configure only. * src/Makefile.am (AM_CFLAGS, AM_LDFLAGS): New variables, to make it easier to provide global flag additions.  Use throughout, to uniformly apply coverage flags. * .gitignore: Globally ignore gcov output. * daemon/.gitignore: Simplify. * src/.gitignore: Likewise. * tests/.gitignore: Likewise. ---