Update wording for gcc requirement.

manual/install.texi

@@ -330,16 +330,15 @@ bugs or lack features.
 @item
 GCC 3.4 or newer, GCC 4.1 recommended
 
-The GNU C library can only be compiled with the GNU C compiler family.
-For the 2.3 releases, GCC 3.2 or higher is required; GCC 3.4 is the
-compiler we advise to use for 2.3 versions.
-For the 2.4 release, GCC 3.4 or higher is required; as of this
-writing, GCC 4.1 is the compiler we advise to use for current versions.
+For the 2.4 release or later, GCC 3.4 or higher is required; as of this
+writing, GCC 4.4 is the compiler we advise to use for current versions.
 On certain machines including @code{powerpc64}, compilers prior to GCC
 4.0 have bugs that prevent them compiling the C library code in the
 2.4 release.  On other machines, GCC 4.1 is required to build the C
 library with support for the correct @code{long double} type format;
-these include @code{powerpc} (32 bit), @code{s390} and @code{s390x}.
+these include @code{powerpc} (32 bit), @code{s390} and @code{s390x}.  For
+other architectures special compiler-provided headers are needed
+(like @file{cpuid.h} on x86) which only come with later compiler versions.
 
 You can use whatever compiler you like to compile programs that use GNU
 libc, but be aware that both GCC 2.7 and 2.8 have bugs in their