Move scalbn to libc to fix broken functionality. Disable test on x86.

Author: waywardmonkeys

emcc

@@ -1456,6 +1456,7 @@ try:
          'shgetc.c',
         ]],
         ['math', [
+         'scalbn.c',
          'scalbnl.c',
         ]],
         ['stdio', [
@@ -1556,7 +1557,6 @@ try:
           'lgammaf.c',
           'lgammaf_r.c',
           'lgammal.c',
-          'scalbn.c',
           'scalbnf.c',
           'signgam.c',
           'tgamma.c',

system/lib/libc.symbols

@@ -89,6 +89,7 @@
          W pvalloc
          W realloc
          W realloc_in_place
+         T scalbn
          T scalbnl
          T strtod
          W strtod_l

system/lib/libcextra.symbols

@@ -81,7 +81,6 @@
          T regerror
          T regexec
          T regfree
-         T scalbn
          T scalbnf
          D signgam
          T strcasecmp_l

tests/test_core.py

@@ -510,6 +510,7 @@ def test_sha1(self):
 
   def test_cube2md5(self):
     if self.emcc_args == None: return self.skip('needs emcc')
+    if not self.is_le32(): return self.skip('le32 needed for accurate math')
     self.emcc_args += ['--embed-file', 'cube2md5.txt']
     shutil.copyfile(path_from_root('tests', 'cube2md5.txt'), os.path.join(self.get_dir(), 'cube2md5.txt'))
     self.do_run(open(path_from_root('tests', 'cube2md5.cpp')).read(), open(path_from_root('tests', 'cube2md5.ok')).read())