Makefile: statically link pthread library for cygwin

In recent mingw g++ compilers from cygwin, the standard C++ library
depends on the pthreads library (libwinpthread-1.dll). As we'd like
for the prism DLLs to not depend on that library, we adapt the
linker flags to statically link the pthread library.

As we are not actually using any symbols, we also have to use the
--whole-archive flag to force linking.

https://stackoverflow.com/questions/13768515/how-to-do-static-linking-of-libwinpthread-1-dll-in-mingw/43402308#43402308


git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@12009 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/Makefile

@@ -212,7 +212,7 @@ ifeq ($(OSTYPE),cygwin)
 		CUDD_XCFLAGS = -fPIC -DPIC -malign-double -DHAVE_IEEE_754 -DHAVE_GETRLIMIT=0 -DRLIMIT_DATA_DEFAULT=268435456 -DHAVE_SYS_RESOURCE_H=0 -DHAVE_SYS_WAIT_H=0 -DSIZEOF_VOID_P=8 -DSIZEOF_LONG=4 -fpermissive $(DEBUG) -static-libgcc -static-libstdc++
 		CFLAGS = $(CUDD_XCFLAGS) $(OPTIMISE)
 		CPPFLAGS = $(CUDD_XCFLAGS) $(OPTIMISE)
-		LDFLAGS = $(CUDD_XCFLAGS) $(OPTIMISE) -Wl,--add-stdcall-alias
+		LDFLAGS = $(CUDD_XCFLAGS) $(OPTIMISE) -Wl,--add-stdcall-alias -Wl,-Bstatic,--whole-archive -lpthread -Wl,-Bdynamic,--no-whole-archive
 		BINDISTSUFFIX = win64
 	else
 		C = /usr/bin/i686-w64-mingw32-gcc
@@ -220,7 +220,7 @@ ifeq ($(OSTYPE),cygwin)
 		CUDD_XCFLAGS = -march=i686 -malign-double -DHAVE_IEEE_754 -DHAVE_GETRLIMIT=0 -DRLIMIT_DATA_DEFAULT=268435456 -DHAVE_SYS_RESOURCE_H=0 -DHAVE_SYS_WAIT_H=0 $(DEBUG) -static-libgcc -static-libstdc++
 		CFLAGS = $(CUDD_XCFLAGS) $(OPTIMISE)
 		CPPFLAGS = $(CUDD_XCFLAGS) $(OPTIMISE)
-		LDFLAGS = $(CUDD_XCFLAGS) $(OPTIMISE) -Wl,--add-stdcall-alias
+		LDFLAGS = $(CUDD_XCFLAGS) $(OPTIMISE) -Wl,--add-stdcall-alias -Wl,-Bstatic,--whole-archive -lpthread -Wl,-Bdynamic,--no-whole-archive
 		BINDISTSUFFIX = win32
 	endif
 	BIN_TARGETS=prism.cygwin xprism.linux prism.bat.win xprism.bat.win