diff --git a/scripts/generateSingleHeader.py b/scripts/generateSingleHeader.py
index dda16305..9f5ddcb0 100644
--- a/scripts/generateSingleHeader.py
+++ b/scripts/generateSingleHeader.py
@@ -14,7 +14,7 @@ guardParser = re.compile( r'\s*#.*TWOBLUECUBES_CATCH_.*_INCLUDED')
 defineParser = re.compile( r'\s*#define')
 ifParser = re.compile( r'\s*#ifndef TWOBLUECUBES_CATCH_.*_INCLUDED')
 endIfParser = re.compile( r'\s*#endif // TWOBLUECUBES_CATCH_.*_INCLUDED')
-ifImplParser = re.compile( r'\s*#if.*(CATCH_CONFIG_MAIN|CATCH_CONFIG_RUNNER)')
+ifImplParser = re.compile( r'\s*#ifdef CATCH_CONFIG_RUNNER' )
 commentParser1 = re.compile( r'^\s*/\*')
 commentParser2 = re.compile( r'^\s*\*')
 blankParser = re.compile( r'^\s*$')
@@ -59,6 +59,8 @@ def parseFile( path, filename ):
             ifdefs = ifdefs + 1
         elif endIfParser.match( line ):
             ifdefs = ifdefs - 1
+            if ifdefs == implIfDefs:
+                implIfDefs = -1
         m = includesParser.match( line )
         if m:
             header = m.group(1)