I want to compile a pure 64bit HLFS system
With 64-bit LiveCD boot, then use HLFS the Book, configure gcc with ../cocoon-toolchain/configure --prefix=/tools \
--with-local-prefix=/tools --enable-clocale=gnu \
--enable-shared --enable-threads=posix \
--enable-__cxa_atexit --enable-languages=c,c++ \
--with-lib-path=/tools/lib --disable-libstdcxx-pch \
--enable-checking --disable-werror \
--enable-64-bit-bfd --disable-multilib --disable-nls
at the step of Cocoon Toolchain . Then make .
At the time of Configuring in x86_64-unknown-linux-gnu/libstdc + +-v3 the error appear :
checking for sin in-lm ... configure: error: Link tests are not allowed after GCC_NO_EXECUTABLES.

Are the CLFS 64-bit patchs required ?
Should I following the clfs book with hlfs patches or using the hlfs book with clfs-64bit patches ?
I do not quite understand the principle . To learn from you ~ ~

Though I haven't attempted something like this myself, I believe you would begin with CLFS and then use what you can from HLFS. This thread seems to confirm that, and while it doesn't offer detailed instructions, it should hopefully provide you with some valuable hints.