Hunk 1: enable webassembly on OpenBSD

Hunk 2: don't link against libatomic with clang, which uses libcompiler-rt
at least on OpenBSD.  The heuristic used is that llvm_version will be different
from "0.0" if llvm (clang) is detected.

Index: tools/v8_gypfiles/v8.gyp
--- tools/v8_gypfiles/v8.gyp.orig
+++ tools/v8_gypfiles/v8.gyp
@@ -796,7 +796,7 @@
             }],
             ['v8_enable_webassembly==1', {
               'conditions': [
-                ['OS=="linux" or OS=="mac" or OS=="ios" or OS=="freebsd"', {
+                ['OS=="linux" or OS=="mac" or OS=="ios" or OS=="freebsd" or OS=="openbsd"', {
                   'sources': [
                     '<!@pymod_do_main(GN-scraper "<(V8_ROOT)/BUILD.gn"  "\\"v8_base_without_compiler.*?v8_current_cpu == \\"x64\\".*?v8_enable_webassembly.*?is_linux.*?sources \\+= ")',
                   ],
@@ -947,7 +947,7 @@
         }],
         # Platforms that don't have Compare-And-Swap (CAS) support need to link atomic library
         # to implement atomic memory access
-        ['v8_current_cpu in ["mips", "mipsel", "mips64", "mips64el", "ppc", "arm", "riscv64"]', {
+        ['v8_current_cpu in ["mips", "mipsel", "mips64", "mips64el", "ppc", "arm", "riscv64"] and llvm_version == "0.0"', {
           'link_settings': {
             'libraries': ['-latomic', ],
           },
