spec: Show cmake build options and install them into doc (build-options.txt)

For example, do we have 'LLAMA_AVX2=OFF'?

Signed-off-by: Vitaly Chikunov <vt@altlinux.org>

.gear/llama.cpp.spec

@@ -67,6 +67,7 @@ Overall this is all raw and EXPERIMENTAL, no warranty, no support.
 
 %build
 %cmake
+grep ^LLAMA %_cmake__builddir/CMakeCache.txt | sort | tee build-options.txt
 %cmake_build
 find -name '*.py' | xargs sed -i '1s|#!/usr/bin/env python3|#!%__python3|'
 
@@ -116,7 +117,7 @@ EOF
 
 %files
 %define _customdocdir %_docdir/%name
-%doc LICENSE README.md docs
+%doc LICENSE README.md docs build-options.txt
 %_bindir/llama-*
 %_bindir/convert-*.py
 %_unitdir/llama.service