[CMake] How to set different install scripts into different component RPMs

[徐亮]

I have a big project that include lib1, lib2, app1, app2.
Before CPack 2.8.4, app1 and app2 have standalone CMakeLists.txt and
pack RPM independently. So I can set  different pre/post install
scripts to these RPMs.
In CPack 2.8.4, I can generate two component RPM for app1 and app2.
But how to set different pre/post install scripts to components.

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Liang Xu