Introduce regexp=interpreted to GYP to enable building with interpreted regexp engine.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 7f084b8c1dbbd5b64b8e67a1b8150fbfccfba27b..98cc8cb3b59d7e3b21edd9f5bc8132938153fa31 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -95,6 +95,10 @@
 
     # For a shared library build, results in "libv8-<(soname_version).so".
     'soname_version%': '',
+    
+    # Interpreted regexp engine exists as platform-independent alternative
+    # based where the regular expression is compiled to a bytecode.
+    'v8_interpreted_regexp%': 0,
   },
   'target_defaults': {
     'conditions': [
@@ -110,6 +114,9 @@
       ['v8_enable_gdbjit==1', {
         'defines': ['ENABLE_GDB_JIT_INTERFACE',],
       }],
+      ['v8_interpreted_regexp==1', {
+        'defines': ['V8_INTERPRETED_REGEXP',],
+      }],
       ['v8_target_arch=="arm"', {
         'defines': [
           'V8_TARGET_ARCH_ARM',