build: explaining the linux build.

scripts/build/build-all.sh

@@ -35,6 +35,8 @@ go run build.go -goarch arm64 -cc ${CCARM64} ${OPT} build
 go run build.go -goos darwin -cc ${CCOSX64} ${OPT} build
 
 go run build.go -goos windows -cc ${CCWIN64} ${OPT} build
+
+# Do not remove CC from the linux build, its there for compatibility with Centos6
 CC=${CCX64} go run build.go ${OPT} build
 
 yarn install --pure-lockfile --no-progress