[llvm] Upgrade to LLVM 9.0.1. Use python3 for build. Fixes JB#48595

Build using ninja and only limit number of parallel builds in linking.
Do not enable debug symbols to limit memory usage.
Link binaries dynamically to minimize binary sizes.
Remove obsolete patch.

.gitmodules

@@ -1,3 +1,3 @@
 [submodule "llvm"]
 	path = llvm
-	url = https://git.merproject.org/mirror/llvm-project.git
+	url = https://git.sailfishos.org/mirror/llvm-project.git

rpm/llvm.spec

@@ -11,18 +11,17 @@
 %endif
 
 Name: llvm
-Version: 7.0.1
+Version: 9.0.1
 Release: 0
 Summary: The Low Level Virtual Machine (An Optimizing Compiler Infrastructure)
 License: University of Illinois/NCSA Open Source License
 Group: Development/Tools
 URL: http://llvm.org/
 Source: %{version}/%{name}-%{version}.tar.gz
-Patch1: nosse4-avx.patch
 Requires(post): /sbin/ldconfig
 Requires(postun): /sbin/ldconfig
-BuildRequires: cmake
-BuildRequires: gcc, python
+BuildRequires: cmake, ninja
+BuildRequires: gcc, python3-base
 
 %description
 LLVM is a compiler infrastructure designed for compile-time, link-time, runtime,
@@ -50,28 +49,34 @@ LLVM Header files
 mkdir -p build
 pushd build
 
-%cmake .. -G "Unix Makefiles" \
+# Decrease debuginfo verbosity to reduce memory consumption during final library linking
+%global optflags %(echo %{optflags} | sed 's/-g /-g0 /')
+
+%cmake .. -G Ninja \
 -DBUILD_SHARED_LIBS:BOOL=OFF \
 -DCMAKE_BUILD_TYPE=Release \
+-DCMAKE_INSTALL_RPATH=";" \
+-DCMAKE_C_FLAGS="%{optflags} -DNDEBUG" \
+-DCMAKE_CXX_FLAGS="%{optflags} -DNDEBUG" \
 -DLLVM_BUILD_DOCS:BOOL=OFF \
--DLLVM_BUILD_LLVM_DYLIB:BOOL=OFF \
+-DLLVM_BUILD_LLVM_DYLIB:BOOL=ON \
 -DLLVM_BUILD_RUNTIME:BOOL=OFF \
 -DLLVM_ENABLE_ASSERTIONS:BOOL=OFF \
 -DLLVM_INCLUDE_BENCHMARKS:BOOL=OFF \
 -DLLVM_INCLUDE_DIRS:PATH=%{_includedir} \
 -DLLVM_INCLUDE_EXAMPLES:BOOL=OFF \
 -DLLVM_INCLUDE_TEST:BOOL=OFF \
--DLLVM_LINK_LLVM_DYLIB:BOOL=OFF \
+-DLLVM_LINK_LLVM_DYLIB:BOOL=ON \
+-DLLVM_PARALLEL_LINK_JOBS=1 \
 -DLLVM_TARGETS_TO_BUILD="%{llvm_targets}" \
 -DLLVM_TOOLS_BINARY_DIR:PATH=%{_bindir}
 
-# Jobs limited to 4 to prevent OBS from running out of memory
-make -j4
+%ninja_build
 popd build
 
 %install
 rm -rf %{buildroot}
-make -C build install/strip DESTDIR=%{buildroot}
+%ninja_install -C build
 
 %post -p /sbin/ldconfig
 
@@ -81,12 +86,14 @@ make -C build install/strip DESTDIR=%{buildroot}
 %defattr(-, root, root)
 %{_bindir}/*
 %{_libdir}/*.so.*
+%{_libdir}/libLLVM-*.so
 %{_datadir}/opt-viewer
 
 %files devel
 %defattr(-, root, root)
 %{_libdir}/*.a
 %{_libdir}/*.so
+%exclude %{_libdir}/libLLVM-*.so
 %{_includedir}/llvm
 %{_includedir}/llvm-c
 %{_libdir}/cmake