Disable LTO for riscv64 (no gold linker support)

Signed-off-by: David Abdurachmanov <david.abdurachmanov@sifive.com>

libcxxabi.spec

@@ -6,7 +6,7 @@
 
 Name:		libcxxabi
 Version:	11.0.0
-Release:	%{baserelease}%{?rc_ver:.rc%{rc_ver}}%{?dist}
+Release:	%{baserelease}%{?rc_ver:.rc%{rc_ver}}.0.riscv64%{?dist}
 Summary:	Low level support for a standard C++ library
 License:	MIT or NCSA
 URL:		http://libcxxabi.llvm.org/
@@ -62,6 +62,13 @@ sed -i 's|${LLVM_BINARY_DIR}/share/llvm/cmake|%{_libdir}/cmake/llvm|g' CMakeList
 sed -i 's|#define _LIBCXXABI_ARM_EHABI||g' include/__cxxabi_config.h
 %endif
 
+%ifarch riscv64
+# Disable LTO on RISC-V.
+# RISC-V does not have gold linker support.
+# /usr/bin/ld: /usr/bin/../lib64/LLVMgold.so: error loading plugin: /usr/bin/../lib64/LLVMgold.so: cannot open shared object file: No such file or directory
+%global _lto_cflags %{nil}
+%endif
+
 %ifarch s390 s390x
 %if 0%{?fedora} < 26
 # clang requires z10 at minimum
@@ -105,6 +112,9 @@ cp -a include/* %{buildroot}%{_includedir}
 %{_libdir}/libc++abi.a
 
 %changelog
+* Fri Apr 16 2021 David Abdurachmanov <david.abdurachmanov@gmail.com> - 11.0.0-1.0.riscv64
+- Disable LTO for RISC-V due to lack of gold linker
+
 * Thu Oct 15 2020 sguelton@redhat.com - 11.0.0-1
 - Fix NVR