try to link symlink and use a define on error

fixes compiling with Minimalist GNU win32 (cross) compiler 4.2.1, which
defines symlink, but doesn't implement it.
workaround for missing #warning on windows
build silently by default
check for alloca
check for strcasecmp
Include the module name in the extracted ASN.1 file.
regenerated tests based on Wim L patch
merged patch #31
Merged http://github.com/vlm/asn1c/pull/31: compiling on Win32.
Makefile.am is not needed here
formatted changelog
Merge branch 'master' of https://github.com/wiml/asn1c into wiml-master
ENUMERATED is no longer needed forLDAP3 and MEGACO
Merge https://github.com/vlm/asn1c/pull/37
intentional
issue/32 fchmod() does not respect umask