add force_assert() to enforce assertions as simple assert()s are disabled by -DNDEBUG (fixes #2546)

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2948 152afb58-edef-0310-8abb-c4023f1b3aa9
fix r2943 (added invalid read after free)

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2949 152afb58-edef-0310-8abb-c4023f1b3aa9
[mod_scgi] use goto error for all error cases in mod_scgi_set_defaults

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2950 152afb58-edef-0310-8abb-c4023f1b3aa9
[mod_cml_lua] fix null pointer dereference

  a local lua script could trigger it by not sending any files and not
  setting a last-modified header, leading to zero mtime and a buffer
  ptr = NULL which was used in http_response_handle_cachable

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2951 152afb58-edef-0310-8abb-c4023f1b3aa9
force assertion: setting FD_CLOEXEC must work (if available)

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2952 152afb58-edef-0310-8abb-c4023f1b3aa9
[network] check return value of lseek()

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2953 152afb58-edef-0310-8abb-c4023f1b3aa9
fix unchecked return values from stream_open/stat_cache_get_entry

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2954 152afb58-edef-0310-8abb-c4023f1b3aa9
[mod_webdav] fix logic error in handling file creation error

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2955 152afb58-edef-0310-8abb-c4023f1b3aa9
[mod_accesslog] don't close fd -1

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2956 152afb58-edef-0310-8abb-c4023f1b3aa9
add some asserts to help static analyzers

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2957 152afb58-edef-0310-8abb-c4023f1b3aa9
check length of unix domain socket filenames

From: Stefan Bühler <stbuehler@web.de>

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2958 152afb58-edef-0310-8abb-c4023f1b3aa9