binding.gyp.cmake: fix compilation when not setting target_arch
binding.gyp.cmake: fix compilation when not setting target_arch

NPM package now only builds x86 builds, but for npm those are the only ones
that have ever worked due to a rework of the cmake code generating the
binding.gyp file is required

Signed-off-by: Brendan Le Foll <3e0e8c4069934e8b47d99704927a85c66c0ceb33@intel.com>

matt-auld/mraa,tripzero/mraa,ncrastanaren/mraa,Pillar1989/mraa,neuberfran/mraa,yoyojacky/mraa,spitfire88/mraa,ProfFan/mraa,mircea/mraa,pctj101/mraa,Hbrinj/mraa,arfoll/mraa,yoyojacky/mraa,w4ilun/mraa,Meirtz/mraa,pctj101/mraa,allela-roy/mraa,neuroidss/mraa,g-vidal/mraa,jontrulson/mraa,arfoll/mraa,smileboywtu/mraa,Jon-ICS/mraa,intel-iot-devkit/mraa,damcclos/mraa,sergev/mraa,stefan-andritoiu/mraa-gpio-chardev,yongli3/mraa,anonymouse64/mraa,stefan-andritoiu/mraa-gpio-chardev,jontrulson/mraa,intel-iot-devkit/mraa,petreeftime/mraa,w4ilun/mraa,KurtE/mraa,zBMNForks/mraa,yongli3/mraa,sundw2014/mraa,noahchense/mraa,petreeftime/mraa,whbruce/mraa,noahchense/mraa,spitfire88/mraa,anonymouse64/mraa,stefan-andritoiu/mraa,nioinnovation/mraa,andreivasiliu2211/mraa,sergev/mraa,w4ilun/mraa,alexandru-elisei/mraa,neuroidss/mraa,ProfFan/mraa,noahchense/mraa,sergev/mraa,malikabhi05/mraa,Meirtz/mraa,sundw2014/mraa,STANAPO/mraa,petreeftime/mraa,smileboywtu/mraa,jontrulson/mraa,Kiritoalex/mraa,ncrastanaren/mraa,alexandru-elisei/mraa,malikabhi05/mraa,yongli3/mraa,arunlee77/mraa,arfoll/mraa,neuberfran/mraa,sundw2014/mraa,anonymouse64/mraa,Kiritoalex/mraa,petreeftime/mraa,spitfire88/mraa,arunlee77/mraa,KurtE/mraa,Pillar1989/mraa,SyrianSpock/mraa,zBMNForks/mraa,stefan-andritoiu/mraa,g-vidal/mraa,allela-roy/mraa,spitfire88/mraa,pctj101/mraa,matt-auld/mraa,sundw2014/mraa,matt-auld/mraa,alexandru-elisei/mraa,arunlee77/mraa,alexandru-elisei/mraa,stefan-andritoiu/mraa-gpio-chardev,yoyojacky/mraa,g-vidal/mraa,SyrianSpock/mraa,pctj101/mraa,mircea/mraa,malikabhi05/mraa,neuberfran/mraa,alext-mkrs/mraa,ncrastanaren/mraa,neuberfran/mraa,tripzero/mraa,Kiritoalex/mraa,Hbrinj/mraa,Jon-ICS/mraa,allela-roy/mraa,ncrastanaren/mraa,alext-mkrs/mraa,sergev/mraa,STANAPO/mraa,KurtE/mraa,g-vidal/mraa,sundw2014/mraa,stefan-andritoiu/mraa-gpio-chardev,Propanu/mraa,KurtE/mraa,yongli3/mraa,ncrastanaren/mraa,Propanu/mraa,jontrulson/mraa,intel-iot-devkit/mraa,nioinnovation/mraa,ProfFan/mraa,mircea/mraa,Jon-ICS/mraa,stefan-andritoiu/mraa,SyrianSpock/mraa,alex1818/mraa,alex1818/mraa,Pillar1989/mraa,neuroidss/mraa,zBMNForks/mraa,alexandru-elisei/mraa,intel-iot-devkit/mraa,Hbrinj/mraa,arfoll/mraa,Propanu/mraa,andreivasiliu2211/mraa,whbruce/mraa,w4ilun/mraa,Propanu/mraa,yongli3/mraa,alex1818/mraa,Propanu/mraa,ProfFan/mraa,whbruce/mraa,stefan-andritoiu/mraa-gpio-chardev,whbruce/mraa,damcclos/mraa,jontrulson/mraa,neuberfran/mraa,alext-mkrs/mraa,smileboywtu/mraa,noahchense/mraa,andreivasiliu2211/mraa,sergev/mraa,tripzero/mraa,arfoll/mraa,pctj101/mraa,malikabhi05/mraa,stefan-andritoiu/mraa,alext-mkrs/mraa,andreivasiliu2211/mraa,stefan-andritoiu/mraa,arunlee77/mraa,Hbrinj/mraa,damcclos/mraa,noahchense/mraa,malikabhi05/mraa,nioinnovation/mraa,STANAPO/mraa,g-vidal/mraa,Meirtz/mraa,KurtE/mraa,alext-mkrs/mraa,intel-iot-devkit/mraa