Export compiler command lines in DXR-specific env variables.
Export compiler command lines in DXR-specific env variables.

Rather than just export CC and CXX environment variables, export the
same information as DXR-specific environment variables.  This helps
integration into non-GNU build systems.

jay-z007/dxr,jonasfj/dxr,pelmers/dxr,kleintom/dxr,KiemVM/Mozilla--dxr,jonasfj/dxr,pelmers/dxr,pombredanne/dxr,gartung/dxr,srenatus/dxr,pombredanne/dxr,KiemVM/Mozilla--dxr,gartung/dxr,gartung/dxr,KiemVM/Mozilla--dxr,jay-z007/dxr,gartung/dxr,erikrose/dxr,jbradberry/dxr,erikrose/dxr,nrc/dxr,jonasfj/dxr,bozzmob/dxr,srenatus/dxr,gartung/dxr,nrc/dxr,erikrose/dxr,bozzmob/dxr,pelmers/dxr,nrc/dxr,pombredanne/dxr,bozzmob/dxr,jonasfj/dxr,jbradberry/dxr,jonasfj/dxr,bozzmob/dxr,jbradberry/dxr,kleintom/dxr,bozzmob/dxr,jay-z007/dxr,srenatus/dxr,jbradberry/dxr,pombredanne/dxr,pelmers/dxr,bozzmob/dxr,jonasfj/dxr,jay-z007/dxr,gartung/dxr,bozzmob/dxr,pombredanne/dxr,nrc/dxr,KiemVM/Mozilla--dxr,pombredanne/dxr,pombredanne/dxr,srenatus/dxr,srenatus/dxr,jbradberry/dxr,kleintom/dxr,pelmers/dxr,jay-z007/dxr,nrc/dxr,erikrose/dxr,pelmers/dxr,kleintom/dxr,kleintom/dxr,erikrose/dxr,kleintom/dxr,KiemVM/Mozilla--dxr,jay-z007/dxr,jbradberry/dxr,srenatus/dxr,kleintom/dxr,nrc/dxr,jay-z007/dxr,KiemVM/Mozilla--dxr,gartung/dxr,jbradberry/dxr,pelmers/dxr