Fix Mac build.
Fix Mac build.

The new line in the set(CMAKE_CXX_FLAGS...) line was getting insert
verbatim into the Makefile. Makefiles don't like new lines in their
assignment operators.

The newline escape fix works for CMake 3.0 and above, but since
we support 2.x, we need to use the legacy solution, which is to
split into two separate statements.

Tested: cmake -G"Unix Makefiles" works now on Mac.
Change-Id: I6f4655981b85087c4760c3d26ed0c97c4469ba93

bog-dan-ro/flatbuffers,google/flatbuffers,google/flatbuffers,alexames/flatbuffers,jekinchen/flatjni,evolutional/flatbuffers,bog-dan-ro/flatbuffers,chenkai036/flatbuffers,evolutional/flatbuffers,DavadDi/flatbuffers,zarianw/flatbuffers,evolutional/flatbuffers,endorph-soft/flatbuffers,chenkai036/flatbuffers,jbrads/flatbuffers,FrankStain/flatbuffers,alexames/flatbuffers,rw/flatbuffers,eburkitt/flatbuffers,fuchsia-mirror/third_party-flatbuffers,jekinchen/flatjni,evolutional/flatbuffers,zarianw/flatbuffers,alexames/flatbuffers,google/flatbuffers,google/flatbuffers,chenkai036/flatbuffers,pjulien/flatbuffers,stewartmiles/flatbuffers,royalharsh/flatbuffers,endorph-soft/flatbuffers,SinbadFreedom/FlatBuffer,royalharsh/flatbuffers,jbrads/flatbuffers,pjulien/flatbuffers,google/flatbuffers,google/flatbuffers,fuchsia-mirror/third_party-flatbuffers,pjulien/flatbuffers,jbrads/flatbuffers,jasonstubbs/flatbuffers,SinbadFreedom/FlatBuffer,google/flatbuffers,bog-dan-ro/flatbuffers,alexames/flatbuffers,pjulien/flatbuffers,SinbadFreedom/FlatBuffer,jekinchen/flatjni,royalharsh/flatbuffers,eburkitt/flatbuffers,rw/flatbuffers,rw/flatbuffers,SinbadFreedom/FlatBuffer,endorph-soft/flatbuffers,FrankStain/flatbuffers,MiCHiLU/flatbuffers,jasonstubbs/flatbuffers,jekinchen/flatjni,benssson/flatbuffers,google/flatbuffers,eburkitt/flatbuffers,jbrads/flatbuffers,fuchsia-mirror/third_party-flatbuffers,google/flatbuffers,zarianw/flatbuffers,pjulien/flatbuffers,eburkitt/flatbuffers,jasonstubbs/flatbuffers,royalharsh/flatbuffers,eburkitt/flatbuffers,FrankStain/flatbuffers,MiCHiLU/flatbuffers,stewartmiles/flatbuffers,DavadDi/flatbuffers,endorph-soft/flatbuffers,hgl888/flatbuffers,chenkai036/flatbuffers,hgl888/flatbuffers,zarianw/flatbuffers,pjulien/flatbuffers,FrankStain/flatbuffers,bog-dan-ro/flatbuffers,vitalyisaev2/flatbuffers,zarianw/flatbuffers,rw/flatbuffers,jasonstubbs/flatbuffers,alexames/flatbuffers,jbrads/flatbuffers,MiCHiLU/flatbuffers,rw/flatbuffers,MiCHiLU/flatbuffers,royalharsh/flatbuffers,google/flatbuffers,MiCHiLU/flatbuffers,rw/flatbuffers,benssson/flatbuffers,FrankStain/flatbuffers,kiyoto-suzuki/flatbuffers,evolutional/flatbuffers,alexames/flatbuffers,rw/flatbuffers,pjulien/flatbuffers,eburkitt/flatbuffers,fuchsia-mirror/third_party-flatbuffers,MiCHiLU/flatbuffers,royalharsh/flatbuffers,google/flatbuffers,eburkitt/flatbuffers,benssson/flatbuffers,vitalyisaev2/flatbuffers,endorph-soft/flatbuffers,jekinchen/flatjni,chenkai036/flatbuffers,rw/flatbuffers,alexames/flatbuffers,fuchsia-mirror/third_party-flatbuffers,google/flatbuffers,benssson/flatbuffers,stewartmiles/flatbuffers,chenkai036/flatbuffers,royalharsh/flatbuffers,benssson/flatbuffers,jekinchen/flatjni,jekinchen/flatjni,DavadDi/flatbuffers,hgl888/flatbuffers,endorph-soft/flatbuffers,eburkitt/flatbuffers,stewartmiles/flatbuffers,royalharsh/flatbuffers,endorph-soft/flatbuffers,bog-dan-ro/flatbuffers,evolutional/flatbuffers,alexames/flatbuffers,MiCHiLU/flatbuffers,jbrads/flatbuffers,stewartmiles/flatbuffers,endorph-soft/flatbuffers,SinbadFreedom/FlatBuffer,evolutional/flatbuffers,pjulien/flatbuffers,rw/flatbuffers,chenkai036/flatbuffers,SinbadFreedom/FlatBuffer,alexames/flatbuffers,evolutional/flatbuffers,google/flatbuffers,FrankStain/flatbuffers,alexames/flatbuffers,bog-dan-ro/flatbuffers,benssson/flatbuffers,alexames/flatbuffers,alexames/flatbuffers,vitalyisaev2/flatbuffers,endorph-soft/flatbuffers,chenkai036/flatbuffers,kiyoto-suzuki/flatbuffers,vitalyisaev2/flatbuffers,pjulien/flatbuffers,evolutional/flatbuffers,benssson/flatbuffers,vitalyisaev2/flatbuffers,FrankStain/flatbuffers,jasonstubbs/flatbuffers,alexames/flatbuffers,fuchsia-mirror/third_party-flatbuffers,vitalyisaev2/flatbuffers,pjulien/flatbuffers,alexames/flatbuffers,zarianw/flatbuffers,chenkai036/flatbuffers,kiyoto-suzuki/flatbuffers,benssson/flatbuffers,jasonstubbs/flatbuffers,royalharsh/flatbuffers,fuchsia-mirror/third_party-flatbuffers,rw/flatbuffers,SinbadFreedom/FlatBuffer,zarianw/flatbuffers,vitalyisaev2/flatbuffers,evolutional/flatbuffers,hgl888/flatbuffers,hgl888/flatbuffers,jasonstubbs/flatbuffers,hgl888/flatbuffers,stewartmiles/flatbuffers,pjulien/flatbuffers,chenkai036/flatbuffers,royalharsh/flatbuffers,DavadDi/flatbuffers,DavadDi/flatbuffers,kiyoto-suzuki/flatbuffers,pjulien/flatbuffers,stewartmiles/flatbuffers,stewartmiles/flatbuffers,endorph-soft/flatbuffers,alexames/flatbuffers,kiyoto-suzuki/flatbuffers,evolutional/flatbuffers,stewartmiles/flatbuffers,jekinchen/flatjni,FrankStain/flatbuffers,kiyoto-suzuki/flatbuffers,rw/flatbuffers,google/flatbuffers,zarianw/flatbuffers,bog-dan-ro/flatbuffers,kiyoto-suzuki/flatbuffers,vitalyisaev2/flatbuffers,google/flatbuffers,bog-dan-ro/flatbuffers,jekinchen/flatjni,SinbadFreedom/FlatBuffer,stewartmiles/flatbuffers,fuchsia-mirror/third_party-flatbuffers,jbrads/flatbuffers,rw/flatbuffers,stewartmiles/flatbuffers,kiyoto-suzuki/flatbuffers,MiCHiLU/flatbuffers,DavadDi/flatbuffers,stewartmiles/flatbuffers,jasonstubbs/flatbuffers,evolutional/flatbuffers,jbrads/flatbuffers,stewartmiles/flatbuffers,jekinchen/flatjni,kiyoto-suzuki/flatbuffers,evolutional/flatbuffers