From Thom DeCarlo, build fixes for Cygwin.

Make/makedefs

@@ -538,6 +538,7 @@ ifeq ($(OS),CYGWIN)
   C++               = c++
   DEPARG            = -M -DWIN32
   INC               += 
+  LIB               =
   DEF               += -DWIN32 -W -Wall -DNOMINMAX
   OPTF              = -O2 
   DBGF              = -g -DOSG_COMPILE_UNIT_TESTS
@@ -558,7 +559,7 @@ ifeq ($(OS),CYGWIN)
   SOCKET_LIBS       = 
   OTHER_LIBS        = -lOpenThreads
   PNG_LIBS          = -lpng -lz
-  JPEG_LIBS         = -ljpeg
+  JPEG_LIBS         = -L/usr/local/lib -ljpeg
   GIF_LIBS          = -lungif
   TIFF_LIB          = -ltiff -lz -ljpeg
 

src/osgPlugins/net/sockstream.cpp

@@ -64,7 +64,7 @@
 #include <sstream>
 #include <string>
 
-#if (defined(__APPLE__)&&(__GNUC__<4)) || defined(WIN32) || defined (__sgi) || defined (__hpux) 
+#if (defined(__APPLE__)&&(__GNUC__<4)) || (defined(WIN32)&&!defined(__CYGWIN__)) || defined (__sgi) || defined (__hpux) 
 typedef int socklen_t;
 #endif