Fix Windows build with ENABLED_SHARED and ENABLE_STATIC

Define SOLV_STATIC_LIB for libsolv_static to avoid an error when
building it for Windows:

/work/libsolv/win32/getopt.c:11:14: error: variable ‘optind’ definition is marked dllimport
/work/libsolv/win32/getopt.c:11:24: error: variable ‘opterr’ definition is marked dllimport
/work/libsolv/win32/getopt.c:11:52: error: variable ‘__optreset’ definition is marked dllimport

Author: jon-turney

src/CMakeLists.txt

@@ -69,6 +69,9 @@ INSTALL (TARGETS libsolv LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR} ARCHIVE DES
 
 IF (ENABLE_STATIC AND NOT DISABLE_SHARED)
 ADD_LIBRARY (libsolv_static STATIC ${libsolv_SRCS})
+IF (WIN32)
+  TARGET_COMPILE_DEFINITIONS(libsolv_static PUBLIC SOLV_STATIC_LIB)
+ENDIF (WIN32)
 SET_TARGET_PROPERTIES(libsolv_static PROPERTIES OUTPUT_NAME "solv")
 SET_TARGET_PROPERTIES(libsolv_static PROPERTIES SOVERSION ${LIBSOLV_SOVERSION})
 INSTALL (TARGETS libsolv_static LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR} ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})