Fix PR1936, a crash on malformed #if.  Thanks to Neil for
noticing this!


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@46256 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Lex/Preprocessor.cpp b/Lex/Preprocessor.cpp
index cb5a350..d831093 100644
--- a/Lex/Preprocessor.cpp
+++ b/Lex/Preprocessor.cpp
@@ -939,9 +939,9 @@
       // an argument value in a macro could expand to ',' or '(' or ')'.
       LexUnexpandedToken(Tok);
       
-      if (Tok.is(tok::eof)) {
+      if (Tok.is(tok::eof) || Tok.is(tok::eom)) { // "#if f(<eof>" & "#if f(\n"
         Diag(MacroName, diag::err_unterm_macro_invoc);
-        // Do not lose the EOF.  Return it to the client.
+        // Do not lose the EOF/EOM.  Return it to the client.
         MacroName = Tok;
         return 0;
       } else if (Tok.is(tok::r_paren)) {