Remove influence of Automake conditionals on conditional dependencies. * m4/gnulib-common.m4 (gl_CONDITIONAL): New macro. (gl_CONDITIONAL_HEADER): Use it instead of AM_CONDITIONAL. * m4/libgmp.m4 (gl_LIBGMP): Likewise. * modules/posix_spawn_file_actions_addfchdir-tests (configure.ac): Likewise. * modules/uchar-c++-tests (configure.ac): Likewise. * gnulib-tool (func_modules_transitive_closure): Don't inhibit conditional dependencies processing on a module that uses an Automake conditional.