pgsql: Blind attempt to fix LLVM dependency in the backend

Blind attempt to fix LLVM dependency in the backend

Commit ecaf7c5df5 removed gram.h from the backend's generated-headers
target. In LLVM builds, this leads to loss of dependency information
when generating .bc files. To fix, add a rule that mirrors ad-hoc .o
dependencies for .bc files as well.

Per cfbot (no buildfarm failures reported)
Analysis by Tom Lane and Andres Freund
Proposed fix by Andres Freund
Discussion: https://www.postgresql.org/message-id/20220914210427.y26tkagmxo5wwbvp%40awork3.anarazel.de

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/16492df70bb25bc99ca3c340a75ba84ca64171b8

Modified Files
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src/backend/common.mk | 1 +
1 file changed, 1 insertion(+)