Mohun Biswas pointed out that --libcurl generated a source code with an int function but without a return statement. While fixing that, I also took care about adding some better comments for the generated code. 
diff --git a/RELEASE-NOTES b/RELEASE-NOTES index c01740d..9e72192 100644 --- a/RELEASE-NOTES +++ b/RELEASE-NOTES 
@@ -40,6 +40,7 @@  o Windows curl builds failed file truncation when retry downloading  o SSL session ID cache memory leak  o bad connection re-use check with environment variable-activated proxy use + o --libcurl now generates a return statement as well    This release includes the following known bugs:   @@ -61,6 +62,6 @@  Robin Johnson, Michal Marek, Ates Goral, Andres Garcia, Rob Crittenden,  Emil Romanus, Alessandro Vesely, Ray Pekowski, Spacen Jasset, Andrew Moise,  Gilles Blanc, David Wright, Vikram Saxena, Mateusz Loskot, Gary Maxwell, - Dmitry Kurochkin + Dmitry Kurochkin, Mohun Biswas    Thanks! (and sorry if I forgot to mention someone)