Solaris doesn't deliver a /usr/bin/cpp.  We have our own cpp in
/usr/lib/cpp, and we deliver GNU cpp in /usr/bin/gcpp, but we might not
find those simply by looking in $PATH.  So if we fail, try extra hard to
execute another cpp.  We try GNU's first, since it's more likely what folks
using pycparser will expect (for instance, it handles C++-style comments).

--- pycparser-2.10/pycparser/__init__.py	Sat Aug  3 06:05:22 2013
+++ pycparser-2.10/pycparser/__init__.py	Fri Apr 11 14:58:36 2014
@@ -10,6 +10,7 @@
 __all__ = ['c_lexer', 'c_parser', 'c_ast']
 __version__ = '2.10'
 
+import errno
 from subprocess import Popen, PIPE
 from .c_parser import CParser
 
@@ -28,29 +29,41 @@
         When successful, returns the preprocessed file's contents.
         Errors from cpp will be printed out.
     """
-    path_list = [cpp_path]
-    if isinstance(cpp_args, list):
-        path_list += cpp_args
-    elif cpp_args != '':
-        path_list += [cpp_args]
-    path_list += [filename]
+    cpp_list = [cpp_path, "/usr/bin/gcpp", "/usr/lib/cpp"]
 
-    try:
-        # Note the use of universal_newlines to treat all newlines
-        # as \n for Python's purpose
-        #
-        pipe = Popen(   path_list,
-                        stdout=PIPE,
-                        universal_newlines=True)
-        text = pipe.communicate()[0]
-    except OSError as e:
+    for cpp_path in cpp_list:
+        path_list = [cpp_path]
+        if isinstance(cpp_args, list):
+            path_list += cpp_args
+        elif cpp_args != '':
+            path_list += [cpp_args]
+        path_list += [filename]
+
+        try:
+            # Note the use of universal_newlines to treat all newlines
+            # as \n for Python's purpose
+            #
+            pipe = Popen(   path_list,
+                            stdout=PIPE,
+                            universal_newlines=True)
+            text = pipe.communicate()[0]
+        except OSError as e:
+            # If cpp couldn't be found, just try the next one.
+            if e.errno == errno.ENOENT:
+                continue
+            # If we ran into some other error, raise a RuntimeError.
+            raise RuntimeError("Unable to invoke 'cpp'.\n" +
+                ('Original error: %s' % e))
+
+        return text
+
+    else:
+        # If we couldn't find a cpp, then raise a RuntimeError.
         raise RuntimeError("Unable to invoke 'cpp'.  " +
             'Make sure its path was passed correctly\n' +
             ('Original error: %s' % e))
 
-    return text
 
-
 def parse_file(filename, use_cpp=False, cpp_path='cpp', cpp_args='',
                parser=None):
     """ Parse a C file using pycparser.