FIX build: add dependencies on ghc_boot_platform.h

ghc/ghc.mk

@@ -104,6 +104,11 @@ ghc/stage1/build/tmp/$(ghc_stage1_PROG) : $(compiler_stage1_v_LIB)
 ghc/stage2/build/tmp/$(ghc_stage2_PROG) : $(compiler_stage2_v_LIB)
 ghc/stage3/build/tmp/$(ghc_stage3_PROG) : $(compiler_stage3_v_LIB)
 
+# Modules here import HsVersions.h, so we need ghc_boot_platform.h
+$(ghc_stage1_depfile) : compiler/stage1/$(PLATFORM_H)
+$(ghc_stage2_depfile) : compiler/stage2/$(PLATFORM_H)
+$(ghc_stage3_depfile) : compiler/stage3/$(PLATFORM_H)
+
 all_ghc_stage1 : $(GHC_STAGE1)
 all_ghc_stage2 : $(GHC_STAGE2)
 all_ghc_stage3 : $(GHC_STAGE3)