Fix merge problem; Update compiling COMMON_OPT per review comments.

Makefile.prebuild

@@ -56,7 +56,7 @@ TARGET_FLAGS = -march=rv64gcv0p7_zfh_xtheadc -mabi=lp64d
 endif
 
 ifeq ($(TARGET), x280)
-TARGET_FLAGS = -march=rv64imafdcv_zba_zbb_zfh_xsfvqmaccqoq_xsfvfhbfmin -mabi=lp64d -mcpu=sifive-x280
+TARGET_FLAGS = -march=rv64imafdcv_zba_zbb_zfh -mabi=lp64d
 endif
 
 ifeq ($(TARGET), RISCV64_GENERIC)

Makefile.riscv64

@@ -3,10 +3,10 @@ CCOMMON_OPT += -march=rv64imafdcv0p7_zfh_xtheadc -mabi=lp64d -mtune=c920
 FCOMMON_OPT += -march=rv64imafdcv0p7_zfh_xtheadc -mabi=lp64d -mtune=c920 -static
 endif
 ifeq ($(CORE), x280)
-CCOMMON_OPT += -march=rv64imafdcv_zba_zbb_zfh_xsfvqmaccqoq_xsfvfhbfmin -mabi=lp64d -menable-experimental-extensions -mllvm --riscv-v-vector-bits-min=512 -mcpu=sifive-x280 -ffast-math
-FCOMMON_OPT += -march=rv64imafdcv_zba_zbb_zfh_xsfvqmaccqoq_xsfvfhbfmin -mabi=lp64d -menable-experimental-extensions -static
+CCOMMON_OPT += -march=rv64imafdcv_zba_zbb_zfh -mabi=lp64d -mllvm --riscv-v-vector-bits-min=512 -ffast-math
+FCOMMON_OPT += -march=rv64imafdcv_zba_zbb_zfh -mabi=lp64d -static
 endif
 ifeq ($(CORE), RISCV64_GENERIC)
 CCOMMON_OPT += -march=rv64imafdc -mabi=lp64d
 FCOMMON_OPT += -march=rv64imafdc -mabi=lp64d -static
-endif
+endif

common_riscv64.h

@@ -92,7 +92,7 @@ static inline int blas_quickdivide(blasint x, blasint y){
 #define SEEK_ADDRESS
 
 #if defined(C910V)
-#include <riscv-vector.h>
+#include <riscv_vector.h>
 #endif
 
 #if defined(x280)