0001-Don-t-prematurely-fail-during-configure-due-to-pkg-c.patch

From 382e3e0ed04f43351133fff3f1e6ad6655c6b4e3 Mon Sep 17 00:00:00 2001
From: Julian Ospald <hasufell@posteo.de>
Date: Sat, 9 May 2020 22:48:18 +0200
Subject: [PATCH] Don't prematurely fail during configure due to pkg-config

---
 Cabal/Distribution/Simple/Configure.hs | 32 +++-----------------------
 1 file changed, 3 insertions(+), 29 deletions(-)

diff --git a/Cabal/Distribution/Simple/Configure.hs b/Cabal/Distribution/Simple/Configure.hs
index 7c93c3b4..b7df25da 100644
--- a/Cabal/Distribution/Simple/Configure.hs
+++ b/Cabal/Distribution/Simple/Configure.hs
@@ -1598,7 +1598,6 @@ configurePkgconfigPackages verbosity pkg_descr progdb enabled
     (_, _, progdb') <- requireProgramVersion
                        (lessVerbose verbosity) pkgConfigProgram
                        (orLaterVersion $ mkVersion [0,9,0]) progdb
-    traverse_ requirePkg allpkgs
     mlib' <- traverse addPkgConfigBILib (library pkg_descr)
     libs' <- traverse addPkgConfigBILib (subLibraries pkg_descr)
     exes' <- traverse addPkgConfigBIExe (executables pkg_descr)
@@ -1614,36 +1613,11 @@ configurePkgconfigPackages verbosity pkg_descr progdb enabled
     pkgconfig = getDbProgramOutput (lessVerbose verbosity)
                   pkgConfigProgram progdb
 
-    requirePkg dep@(PkgconfigDependency pkgn range) = do
-      version <- pkgconfig ["--modversion", pkg]
-                 `catchIO`   (\_ -> die' verbosity notFound)
-                 `catchExit` (\_ -> die' verbosity notFound)
-      let trim = dropWhile isSpace . dropWhileEnd isSpace
-      let v = PkgconfigVersion (toUTF8BS $ trim version)
-      if not (withinPkgconfigVersionRange v range)
-      then die' verbosity (badVersion v)
-      else info verbosity (depSatisfied v)
-      where
-        notFound     = "The pkg-config package '" ++ pkg ++ "'"
-                    ++ versionRequirement
-                    ++ " is required but it could not be found."
-        badVersion v = "The pkg-config package '" ++ pkg ++ "'"
-                    ++ versionRequirement
-                    ++ " is required but the version installed on the"
-                    ++ " system is version " ++ prettyShow v
-        depSatisfied v = "Dependency " ++ prettyShow dep
-                      ++ ": using version " ++ prettyShow v
-
-        versionRequirement
-          | isAnyPkgconfigVersion range = ""
-          | otherwise                   = " version " ++ prettyShow range
-
-        pkg = unPkgconfigName pkgn
-
     -- Adds pkgconfig dependencies to the build info for a component
     addPkgConfigBI compBI setCompBI comp = do
-      bi <- pkgconfigBuildInfo (pkgconfigDepends (compBI comp))
-      return $ setCompBI comp (compBI comp `mappend` bi)
+      bi <- fmap Just (pkgconfigBuildInfo (pkgconfigDepends (compBI comp)))
+            <|> pure Nothing
+      return $ setCompBI comp (maybe id (\x y -> mappend y x) bi $ compBI comp)
 
     -- Adds pkgconfig dependencies to the build info for a library
     addPkgConfigBILib = addPkgConfigBI libBuildInfo $
-- 
2.25.0