Backport GCC 4.5+ --enable-linker-build-id option.

gcc/doc/install.texi

 \input texinfo.tex    @c -*-texinfo-*-
 @c @ifnothtml
 @c %**start of header
 @setfilename gccinstall.info
 @settitle Installing GCC
 @setchapternewpage odd
 @c %**end of header
 @c @end ifnothtml
 
 @include gcc-common.texi
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 @samp{-lstdc++} or @samp{-Wl,-Bstatic,-lstdc++,-Bdynamic -lm}.  If you are
 linking with a shared copy of PPL, you probably do not need this
 option; shared library dependencies will cause the linker to search
 for the standard C++ library automatically.
 
 @item --with-debug-prefix-map=@var{map}
 Convert source directory names using @option{-fdebug-prefix-map} when
 building runtime libraries.  @samp{@var{map}} is a space-separated
 list of maps of the form @samp{@var{old}=@var{new}}.
 
+@item --enable-linker-build-id
+Tells GCC to pass @option{--build-id} option to the linker for all final
+links (links performed without the @option{-r} or @option{--relocatable}
+option), if the linker supports it.  If you specify
+@option{--enable-linker-build-id}, but your linker does not
+support @option{--build-id} option, a warning is issued and the
+@option{--enable-linker-build-id} option is ignored.  The default is off.
+
 @end table
 
 @subheading Cross-Compiler-Specific Options
 The following options only apply to building cross compilers.
 @table @code
 @item --with-sysroot
 @itemx --with-sysroot=@var{dir}
 Tells GCC to consider @var{dir} as the root of a tree that contains a
 (subset of) the root filesystem of the target operating system.
 Target system headers, libraries and run-time object files will be
@@ skipping 2812 matching lines @@
 @end ifinfo
 
 @ifinfo
 @unnumbered Concept Index
 
 @printindex cp
 
 @contents
 @end ifinfo
 @bye