build: fix error message in configure

Replace Node.js to io.js in error messages.

Author: Shigeki Ohtsu

configure

@@ -360,7 +360,7 @@ def get_llvm_version(cc):
     proc = subprocess.Popen(shlex.split(cc) + ['-v'], stdin=subprocess.PIPE,
                             stderr=subprocess.PIPE, stdout=subprocess.PIPE)
   except OSError:
-    print '''Node.js configure error: No acceptable C compiler found!
+    print '''io.js configure error: No acceptable C compiler found!
 
         Please make sure you have a C compiler installed on your system and/or
         consider adjusting the CC environment variable if you installed
@@ -385,7 +385,7 @@ def get_gas_version(cc):
                             stdin=subprocess.PIPE, stderr=subprocess.PIPE,
                             stdout=subprocess.PIPE)
   except OSError:
-    print '''Node.js configure error: No acceptable C compiler found!
+    print '''io.js configure error: No acceptable C compiler found!
 
         Please make sure you have a C compiler installed on your system and/or
         consider adjusting the CC environment variable if you installed
@@ -443,7 +443,7 @@ def cc_macros():
                          stdout=subprocess.PIPE,
                          stderr=subprocess.PIPE)
   except OSError:
-    print '''Node.js configure error: No acceptable C compiler found!
+    print '''io.js configure error: No acceptable C compiler found!
 
         Please make sure you have a C compiler installed on your system and/or
         consider adjusting the CC environment variable if you installed