audio/faust: Attempt to fix failure on riscv64

Reported by:	fallout

audio/faust/Makefile

@@ -31,6 +31,7 @@ CMAKE_ARGS=	-C ${FILESDIR}/backends.cmake -DLLVM_CONFIG=${LOCALBASE}/bin/llvm-co
 
 CXXFLAGS+=	-I${WRKSRC}/compiler/generator/cpp # fatal error: 'cpp_code_container.hh' file not found WHEN INCLUDE_STATIC=TRUE
 CXXFLAGS+=	`llvm-config${LLVM_VERSION} --cflags` -DLLVM_${LLVM_VERSION}0 # for the llvm backend
+CXXFLAGS_riscv64=	-fPIC # attempt to fix failure: can't create dynamic relocation R_RISCV_HI20 against symbol: vtable for LV2UI in readonly segment; recompile object files with -fPIC or pass '-Wl,-z,notext' to allow text relocations in the output
 LDFLAGS+=	-lexecinfo
 
 OPTIONS_DEFINE=		EXAMPLES HIGHLIGHT HTTPD_LIB