(program_transform_name, program_transform_cross_name): Define.

(GCC_INSTALL_NAME, GCC_CROSS_NAME): Define.
(install-common): Use them.
(install-man): Likewise.
(distclean): Delete *.asm.
(stage*, risky-stage*): If as/ld/real-ld exist, copy them to stage dir.

From-SVN: r8486