New features:

• Added optional LTO support including -fwhole support on e2k arch: --enable-lto

Bug fixes:

• Fix build on musl, avoid glibc-specific code.
• Do not ignore *-{uid,gid} settings if no CAPABILITIES_SUPPORT.
• Fix potential buffer problems in string and memory operations.
• Fix doxygen issues.
• Fix build using autoconf-2.70.

Other:

• Optimize checks using (un)likely.
• Autogenerate program.h
• Fix various gcc warnings.