fix invalid conversion error with MinGW 4.8.1 in net.cpp
fix invalid conversion error with MinGW 4.8.1 in net.cpp

- fixes src\net.cpp:1601: Error:invalid conversion from 'void*' to
  'const char*' [-fpermissive] in a setsockopt() call on Win32 that was
  found by using MinGW 4.8.1 compiler suite

oklink-dev/litecoin_block,bitgoldcoin-project/bitgoldcoin,Ziftr/litecoin,richo/dongcoin,Rav3nPL/doubloons-08,CrimeaCoin/crimeacoin,alexandrcoin/vertcoin,Coinfigli/coinfigli,oklink-dev/litecoin_block,novaexchange/EAC,privatecoin/privatecoin,shapiroisme/datadollar,coinkeeper/2015-06-22_19-13_florincoin,richo/dongcoin,cryptcoins/cryptcoin,micryon/GPUcoin,shapiroisme/datadollar,DrCrypto/darkcoin,Cancercoin/Cancercoin,marscoin/marscoin,mooncoin-project/mooncoin-landann,netswift/vertcoin,Checkcoin/checkcoin,cryptcoins/cryptcoin,kryptokredyt/ProjektZespolowyCoin,novaexchange/EAC,mrtexaznl/mediterraneancoin,razor-coin/razor,marscoin/marscoin,ANCompany/birdcoin-dev,kryptokredyt/ProjektZespolowyCoin,gwangjin2/gwangcoin-core,Dajackal/Ronpaulcoin,Electronic-Gulden-Foundation/egulden,Rav3nPL/doubloons-08,greencoin-dev/greencoin-dev,dakk/soundcoin,okinc/litecoin,Tetcoin/tetcoin,chrisfranko/aiden,Electronic-Gulden-Foundation/egulden,vertcoin/eyeglass,shurcoin/shurcoin,icook/vertcoin,IlfirinCano/shavercoin,Czarcoin/czarcoin,vertcoin/eyeglass,bitgoldcoin-project/bitgoldcoin,mooncoin-project/mooncoin-landann,ronpaulcoin/ronpaulcoin,ronpaulcoin/ronpaulcoin,brishtiteveja/sherlockholmescoin,alexandrcoin/vertcoin,stamhe/litecoin,privatecoin/privatecoin,Cancercoin/Cancercoin,netswift/vertcoin,ohac/sakuracoin,novaexchange/EAC,Litecoindark/LTCD,Ziftr/litecoin,Electronic-Gulden-Foundation/egulden,coinkeeper/2015-04-19_21-20_litecoindark,bootycoin-project/bootycoin,privatecoin/privatecoin,Rav3nPL/doubloons-08,novaexchange/EAC,Dajackal/Ronpaulcoin,coinkeeper/2015-06-22_18-46_razor,coinkeeper/2015-06-22_18-51_vertcoin,kryptokredyt/ProjektZespolowyCoin,DrCrypto/darkcoin,gwangjin2/gwangcoin-core,Czarcoin/czarcoin,zemrys/vertcoin,coinkeeper/2015-06-22_18-46_razor,Czarcoin/czarcoin,united-scrypt-coin-project/unitedscryptcoin,ohac/sakuracoin,ohac/sha1coin,Czarcoin/czarcoin,koharjidan/litecoin,zzkt/solarcoin,bootycoin-project/bootycoin,chrisfranko/aiden,CrimeaCoin/crimeacoin,degenorate/Deftcoin,shurcoin/shurcoin,gwangjin2/gwangcoin-core,vertcoin/eyeglass,jiffe/cosinecoin,earthcoinproject/earthcoin,oklink-dev/litecoin_block,zebrains/Blotter,united-scrypt-coin-project/unitedscryptcoin,oklink-dev/litecoin_block,cryptcoins/cryptcoin,bootycoin-project/bootycoin,Litecoindark/LTCD,shapiroisme/datadollar,degenorate/Deftcoin,Cancercoin/Cancercoin,Tetcoin/tetcoin,alexandrcoin/vertcoin,ohac/sakuracoin,dakk/soundcoin,coinkeeper/2015-06-22_18-46_razor,coinkeeper/2015-04-19_21-20_litecoindark,scamcoinz/scamcoin,razor-coin/razor,Electronic-Gulden-Foundation/egulden,earthcoinproject/earthcoin,ohac/sakuracoin,shurcoin/shurcoin,scamcoinz/scamcoin,micryon/GPUcoin,Electronic-Gulden-Foundation/egulden,IlfirinIlfirin/shavercoin,marscoin/marscoin,coinkeeper/2015-06-22_19-13_florincoin,tensaix2j/bananacoin,shapiroisme/datadollar,Coinfigli/coinfigli,okinc/litecoin,marscoin/marscoin,plankton12345/litecoin,richo/dongcoin,CrimeaCoin/crimeacoin,united-scrypt-coin-project/unitedscryptcoin,coinkeeper/2015-04-19_21-20_litecoindark,coinkeeper/2015-06-22_18-51_vertcoin,micryon/GPUcoin,degenorate/Deftcoin,mrtexaznl/mediterraneancoin,earthcoinproject/earthcoin,wekuiz/wekoin,brishtiteveja/sherlockholmescoin,wekuiz/wekoin,united-scrypt-coin-project/unitedscryptcoin,jiffe/cosinecoin,plankton12345/litecoin,wekuiz/wekoin,cryptcoins/cryptcoin,bitgoldcoin-project/bitgoldcoin,okinc/litecoin,netswift/vertcoin,DrCrypto/darkcoin,Tetcoin/tetcoin,kryptokredyt/ProjektZespolowyCoin,Ziftr/litecoin,scamcoinz/scamcoin,marscoin/marscoin,oklink-dev/litecoin_block,CrimeaCoin/crimeacoin,united-scrypt-coin-project/unitedscryptcoin,mooncoin-project/mooncoin-landann,Litecoindark/LTCD,ccoin-project/ccoin,IlfirinIlfirin/shavercoin,bitgoldcoin-project/bitgoldcoin,IlfirinCano/shavercoin,coinkeeper/2015-06-22_19-13_florincoin,chrisfranko/aiden,stamhe/litecoin,KaSt/equikoin,KaSt/equikoin,brightcoin/brightcoin,ANCompany/birdcoin-dev,shadowoneau/ozcoin,dakk/soundcoin,shurcoin/shurcoin,plankton12345/litecoin,netswift/vertcoin,coinkeeper/2015-06-22_18-51_vertcoin,Cancercoin/Cancercoin,ccoin-project/ccoin,coinkeeper/2015-04-19_21-20_litecoindark,CrimeaCoin/crimeacoin,koharjidan/litecoin,IlfirinIlfirin/shavercoin,IlfirinCano/shavercoin,shadowoneau/ozcoin,shadowoneau/ozcoin,Checkcoin/checkcoin,DrCrypto/darkcoin,brishtiteveja/sherlockholmescoin,ohac/sha1coin,koharjidan/litecoin,zemrys/vertcoin,ohac/sakuracoin,coinkeeper/2015-06-22_18-51_vertcoin,kryptokredyt/ProjektZespolowyCoin,plankton12345/litecoin,ronpaulcoin/ronpaulcoin,dakk/soundcoin,chrisfranko/aiden,brishtiteveja/sherlockholmescoin,Ziftr/litecoin,icook/vertcoin,mrtexaznl/mediterraneancoin,icook/vertcoin,ANCompany/birdcoin-dev,zzkt/solarcoin,dakk/soundcoin,cryptcoins/cryptcoin,KaSt/equikoin,marscoin/marscoin,ccoin-project/ccoin,bootycoin-project/bootycoin,zebrains/Blotter,coinkeeper/2015-06-22_19-13_florincoin,Rav3nPL/doubloons-08,privatecoin/privatecoin,Coinfigli/coinfigli,neutrinofoundation/neutrino-digital-currency,zebrains/Blotter,mooncoin-project/mooncoin-landann,coinkeeper/2015-06-22_19-13_florincoin,brishtiteveja/sherlockholmescoin,zemrys/vertcoin,richo/dongcoin,zemrys/vertcoin,IlfirinCano/shavercoin,Czarcoin/czarcoin,coinkeeper/2015-06-22_18-46_razor,chrisfranko/aiden,scamcoinz/scamcoin,Checkcoin/checkcoin,ANCompany/birdcoin-dev,zemrys/vertcoin,zemrys/vertcoin,zzkt/solarcoin,ohac/sha1coin,IlfirinIlfirin/shavercoin,privatecoin/privatecoin,shadowoneau/ozcoin,mooncoin-project/mooncoin-landann,icook/vertcoin,tensaix2j/bananacoin,richo/dongcoin,mrtexaznl/mediterraneancoin,gwangjin2/gwangcoin-core,IlfirinCano/shavercoin,wekuiz/wekoin,degenorate/Deftcoin,zzkt/solarcoin,shurcoin/shurcoin,micryon/GPUcoin,stamhe/litecoin,jiffe/cosinecoin,novaexchange/EAC,brightcoin/brightcoin,zebrains/Blotter,icook/vertcoin,okinc/litecoin,netswift/vertcoin,coinkeeper/2015-06-22_18-51_vertcoin,scamcoinz/scamcoin,Checkcoin/checkcoin,ronpaulcoin/ronpaulcoin,gwangjin2/gwangcoin-core,tensaix2j/bananacoin,wekuiz/wekoin,netswift/vertcoin,Rav3nPL/doubloons-08,neutrinofoundation/neutrino-digital-currency,mrtexaznl/mediterraneancoin,tensaix2j/bananacoin,earthcoinproject/earthcoin,zzkt/solarcoin,bootycoin-project/bootycoin,Litecoindark/LTCD,Cancercoin/Cancercoin,ccoin-project/ccoin,Tetcoin/tetcoin,coinkeeper/2015-04-19_21-20_litecoindark,stamhe/litecoin,tensaix2j/bananacoin,IlfirinIlfirin/shavercoin,okinc/litecoin,Dajackal/Ronpaulcoin,coinkeeper/2015-06-22_18-46_razor,earthcoinproject/earthcoin,jiffe/cosinecoin,vertcoin/eyeglass,neutrinofoundation/neutrino-digital-currency,Dajackal/Ronpaulcoin,koharjidan/litecoin,Checkcoin/checkcoin,bitgoldcoin-project/bitgoldcoin,degenorate/Deftcoin,Litecoindark/LTCD,shadowoneau/ozcoin,micryon/GPUcoin,koharjidan/litecoin,Coinfigli/coinfigli,greencoin-dev/greencoin-dev,greencoin-dev/greencoin-dev,ohac/sha1coin,alexandrcoin/vertcoin,koharjidan/litecoin,ANCompany/birdcoin-dev,brightcoin/brightcoin,Electronic-Gulden-Foundation/egulden,razor-coin/razor,neutrinofoundation/neutrino-digital-currency,vertcoin/eyeglass,KaSt/equikoin,shapiroisme/datadollar,greencoin-dev/greencoin-dev,brightcoin/brightcoin,Tetcoin/tetcoin,Ziftr/litecoin,Dajackal/Ronpaulcoin,ohac/sha1coin,razor-coin/razor,ronpaulcoin/ronpaulcoin,KaSt/equikoin,greencoin-dev/greencoin-dev,razor-coin/razor,Coinfigli/coinfigli,brightcoin/brightcoin,zebrains/Blotter,plankton12345/litecoin