build: activate correct default flags for riscv64

Signed-off-by: Stewart X Addison <sxa@ibm.com>
PR-URL: #65708
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Richard Lau <richard.lau@ibm.com>

Author: sxa

common.gypi

@@ -616,6 +616,10 @@
                 'cflags': [ '-m64', '-march=z196' ],
                 'ldflags': [ '-m64', '-march=z196' ],
               }],
+              [ 'host_arch=="riscv64" and OS=="linux"', {
+                'cflags': [ '-march=rv64gc' ],
+                'ldflags': [ '-march=rv64gc' ],
+              }],
             ],
           }],
           ['_toolset=="target"', {
@@ -641,6 +645,10 @@
                 'cflags': [ '-m64', '-march=z196' ],
                 'ldflags': [ '-m64', '-march=z196' ],
               }],
+              [ 'target_arch=="riscv64" and OS=="linux"', {
+                'cflags': [ '-march=rv64gc' ],
+                'ldflags': [ '-march=rv64gc' ],
+              }],
             ],
           }],
         ],

tools/v8_gypfiles/v8.gyp

@@ -2414,6 +2414,9 @@
         ['v8_target_arch=="ppc64" or v8_target_arch=="s390x"', {
           'defines': ['TOOLCHAIN_MISS_ASM_HWCAP_H',],
         }],
+        ['v8_target_arch=="riscv64"', {
+          'defines': ['HWY_BROKEN_TARGETS=HWY_RVV',],
+        }],
       ],
       'sources': [
         '<!@pymod_do_main(GN-scraper "<(HIGHWAY_ROOT)/BUILD.gn"  "source_set.\\"libhwy.*?sources = ")',