#10861: `configure -C` yields different results on second run -------------------------------------+------------------------------------- Reporter: thomie | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Build | Version: 7.10.2 System | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- Autoconf has a feature to cache the results of a configure run (using `configure -C`), and use it in subsequent runs. It greatly speeds up those subsequent runs. * http://www.gnu.org/software/autoconf/manual/autoconf-2.66/html_node /Cache-Files.html#Cache-Files * http://www.gnu.org/software/autoconf/manual/autoconf-2.66/html_node /Caching-Results.html At least the `FP_GCC_VERSION` macro in aclocal.m4 is currently buggy. The call to AC_CACHE_CHECK should only set the cache variable (fp_cv_gcc_version), but it also sets others (GccLT34 and GccLT44) (side question: how do those interact with clang?). This means that subsequent runs of `configure -C` won't use the right values for GccLT34 and GccLT44, when your gcc is actually older than those. There are likely other bugs. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10861 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler